diff --git a/workflow-runtime/api/workflow-runtime.api b/workflow-runtime/api/workflow-runtime.api
index 9e49aaab49..fd61348223 100644
--- a/workflow-runtime/api/workflow-runtime.api
+++ b/workflow-runtime/api/workflow-runtime.api
@@ -5,6 +5,7 @@ public final class com/squareup/workflow1/NoopWorkflowInterceptor : com/squareup
 	public fun onRender (Ljava/lang/Object;Ljava/lang/Object;Lcom/squareup/workflow1/BaseRenderContext;Lkotlin/jvm/functions/Function3;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)Ljava/lang/Object;
 	public fun onRenderAndSnapshot (Ljava/lang/Object;Lkotlin/jvm/functions/Function1;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)Lcom/squareup/workflow1/RenderingAndSnapshot;
 	public fun onRuntimeUpdate (Lcom/squareup/workflow1/WorkflowInterceptor$RuntimeUpdate;)V
+	public fun onSessionCancelled (Ljava/util/concurrent/CancellationException;Ljava/util/List;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)V
 	public fun onSessionStarted (Lkotlinx/coroutines/CoroutineScope;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)V
 	public fun onSnapshotState (Ljava/lang/Object;Lkotlin/jvm/functions/Function1;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)Lcom/squareup/workflow1/Snapshot;
 	public fun onSnapshotStateWithChildren (Lkotlin/jvm/functions/Function0;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)Lcom/squareup/workflow1/TreeSnapshot;
@@ -34,6 +35,7 @@ public class com/squareup/workflow1/SimpleLoggingWorkflowInterceptor : com/squar
 	public fun onRender (Ljava/lang/Object;Ljava/lang/Object;Lcom/squareup/workflow1/BaseRenderContext;Lkotlin/jvm/functions/Function3;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)Ljava/lang/Object;
 	public fun onRenderAndSnapshot (Ljava/lang/Object;Lkotlin/jvm/functions/Function1;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)Lcom/squareup/workflow1/RenderingAndSnapshot;
 	public fun onRuntimeUpdate (Lcom/squareup/workflow1/WorkflowInterceptor$RuntimeUpdate;)V
+	public fun onSessionCancelled (Ljava/util/concurrent/CancellationException;Ljava/util/List;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)V
 	public fun onSessionStarted (Lkotlinx/coroutines/CoroutineScope;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)V
 	public fun onSnapshotState (Ljava/lang/Object;Lkotlin/jvm/functions/Function1;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)Lcom/squareup/workflow1/Snapshot;
 	public fun onSnapshotStateWithChildren (Lkotlin/jvm/functions/Function0;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)Lcom/squareup/workflow1/TreeSnapshot;
@@ -58,6 +60,7 @@ public abstract interface class com/squareup/workflow1/WorkflowInterceptor {
 	public abstract fun onRender (Ljava/lang/Object;Ljava/lang/Object;Lcom/squareup/workflow1/BaseRenderContext;Lkotlin/jvm/functions/Function3;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)Ljava/lang/Object;
 	public abstract fun onRenderAndSnapshot (Ljava/lang/Object;Lkotlin/jvm/functions/Function1;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)Lcom/squareup/workflow1/RenderingAndSnapshot;
 	public abstract fun onRuntimeUpdate (Lcom/squareup/workflow1/WorkflowInterceptor$RuntimeUpdate;)V
+	public abstract fun onSessionCancelled (Ljava/util/concurrent/CancellationException;Ljava/util/List;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)V
 	public abstract fun onSessionStarted (Lkotlinx/coroutines/CoroutineScope;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)V
 	public abstract fun onSnapshotState (Ljava/lang/Object;Lkotlin/jvm/functions/Function1;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)Lcom/squareup/workflow1/Snapshot;
 	public abstract fun onSnapshotStateWithChildren (Lkotlin/jvm/functions/Function0;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)Lcom/squareup/workflow1/TreeSnapshot;
@@ -69,6 +72,7 @@ public final class com/squareup/workflow1/WorkflowInterceptor$DefaultImpls {
 	public static fun onRender (Lcom/squareup/workflow1/WorkflowInterceptor;Ljava/lang/Object;Ljava/lang/Object;Lcom/squareup/workflow1/BaseRenderContext;Lkotlin/jvm/functions/Function3;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)Ljava/lang/Object;
 	public static fun onRenderAndSnapshot (Lcom/squareup/workflow1/WorkflowInterceptor;Ljava/lang/Object;Lkotlin/jvm/functions/Function1;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)Lcom/squareup/workflow1/RenderingAndSnapshot;
 	public static fun onRuntimeUpdate (Lcom/squareup/workflow1/WorkflowInterceptor;Lcom/squareup/workflow1/WorkflowInterceptor$RuntimeUpdate;)V
+	public static fun onSessionCancelled (Lcom/squareup/workflow1/WorkflowInterceptor;Ljava/util/concurrent/CancellationException;Ljava/util/List;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)V
 	public static fun onSessionStarted (Lcom/squareup/workflow1/WorkflowInterceptor;Lkotlinx/coroutines/CoroutineScope;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)V
 	public static fun onSnapshotState (Lcom/squareup/workflow1/WorkflowInterceptor;Ljava/lang/Object;Lkotlin/jvm/functions/Function1;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)Lcom/squareup/workflow1/Snapshot;
 	public static fun onSnapshotStateWithChildren (Lcom/squareup/workflow1/WorkflowInterceptor;Lkotlin/jvm/functions/Function0;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)Lcom/squareup/workflow1/TreeSnapshot;
diff --git a/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/SimpleLoggingWorkflowInterceptor.kt b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/SimpleLoggingWorkflowInterceptor.kt
index 58bb7af703..95b38f0cf0 100644
--- a/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/SimpleLoggingWorkflowInterceptor.kt
+++ b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/SimpleLoggingWorkflowInterceptor.kt
@@ -2,8 +2,8 @@ package com.squareup.workflow1
 
 import com.squareup.workflow1.WorkflowInterceptor.RenderContextInterceptor
 import com.squareup.workflow1.WorkflowInterceptor.WorkflowSession
+import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.Job
 
 /**
  * A [WorkflowInterceptor] that just prints all method calls using [log].
@@ -14,9 +14,14 @@ public open class SimpleLoggingWorkflowInterceptor : WorkflowInterceptor {
     session: WorkflowSession
   ) {
     invokeSafely("logBeforeMethod") { logBeforeMethod("onInstanceStarted", session) }
-    workflowScope.coroutineContext[Job]!!.invokeOnCompletion {
-      invokeSafely("logAfterMethod") { logAfterMethod("onInstanceStarted", session) }
-    }
+  }
+
+  override fun <P, S, O> onSessionCancelled(
+    cause: CancellationException?,
+    droppedActions: List<WorkflowAction<P, S, O>>,
+    session: WorkflowSession
+  ) {
+    invokeSafely("logAfterMethod") { logAfterMethod("onInstanceStarted", session) }
   }
 
   override fun <P, S> onInitialState(
diff --git a/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/WorkflowInterceptor.kt b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/WorkflowInterceptor.kt
index 2347b3531a..d10a3b2682 100644
--- a/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/WorkflowInterceptor.kt
+++ b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/WorkflowInterceptor.kt
@@ -2,6 +2,7 @@ package com.squareup.workflow1
 
 import com.squareup.workflow1.WorkflowInterceptor.RenderContextInterceptor
 import com.squareup.workflow1.WorkflowInterceptor.WorkflowSession
+import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Job
 import kotlin.coroutines.CoroutineContext
@@ -75,6 +76,19 @@ public interface WorkflowInterceptor {
     session: WorkflowSession
   ): Unit = Unit
 
+  /**
+   * Called when the session is ending, when the Workflow's [CoroutineScope] is being cancelled.
+   *
+   * @param cause The cause of the cancellation if non-null.
+   * @param droppedActions Any actions that were queued in this node's channel at the time of
+   *  cancellation.
+   */
+  public fun <P, S, O> onSessionCancelled(
+    cause: CancellationException?,
+    droppedActions: List<WorkflowAction<P, S, O>>,
+    session: WorkflowSession
+  ): Unit = Unit
+
   /**
    * Intercepts calls to [StatefulWorkflow.initialState].
    */
diff --git a/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/ChainedWorkflowInterceptor.kt b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/ChainedWorkflowInterceptor.kt
index f5c4052277..4be61b63e9 100644
--- a/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/ChainedWorkflowInterceptor.kt
+++ b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/ChainedWorkflowInterceptor.kt
@@ -11,6 +11,7 @@ import com.squareup.workflow1.WorkflowInterceptor
 import com.squareup.workflow1.WorkflowInterceptor.RenderContextInterceptor
 import com.squareup.workflow1.WorkflowInterceptor.RuntimeUpdate
 import com.squareup.workflow1.WorkflowInterceptor.WorkflowSession
+import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.CoroutineScope
 import kotlin.reflect.KType
 
@@ -32,6 +33,20 @@ internal class ChainedWorkflowInterceptor(
     interceptors.forEach { it.onSessionStarted(workflowScope, session) }
   }
 
+  override fun <P, S, O> onSessionCancelled(
+    cause: CancellationException?,
+    droppedActions: List<WorkflowAction<P, S, O>>,
+    session: WorkflowSession
+  ) {
+    interceptors.forEach {
+      it.onSessionCancelled(
+        cause = cause,
+        droppedActions = droppedActions,
+        session = session
+      )
+    }
+  }
+
   override fun <P, S> onInitialState(
     props: P,
     snapshot: Snapshot?,
diff --git a/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/WorkflowNode.kt b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/WorkflowNode.kt
index 82d7ebe7ce..1c82b4e171 100644
--- a/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/WorkflowNode.kt
+++ b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/WorkflowNode.kt
@@ -265,10 +265,22 @@ internal class WorkflowNode<PropsT, StateT, OutputT, RenderingT>(
   /**
    * Cancels this state machine host, and any coroutines started as children of it.
    *
-   * This must be called when the caller will no longer call [registerTreeActionSelectors]. It is an error to call [registerTreeActionSelectors]
-   * after calling this method.
+   * This must be called when the caller will no longer call [registerTreeActionSelectors].
+   * It is an error to call [registerTreeActionSelectors] after calling this method.
    */
   fun cancel(cause: CancellationException? = null) {
+    val hangingActions = mutableListOf<WorkflowAction<PropsT, StateT, OutputT>>()
+    // This will only be non-null if there is an action buffered and ready.
+    var nextAction = eventActionsChannel.tryReceive().getOrNull()
+    while (nextAction != null) {
+      hangingActions.add(nextAction)
+      nextAction = eventActionsChannel.tryReceive().getOrNull()
+    }
+    interceptor.onSessionCancelled(
+      cause = cause,
+      droppedActions = hangingActions,
+      session = this
+    )
     coroutineContext.cancel(cause)
     lastRendering = NullableInitBox()
   }
diff --git a/workflow-runtime/src/commonTest/kotlin/com/squareup/workflow1/SimpleLoggingWorkflowInterceptorTest.kt b/workflow-runtime/src/commonTest/kotlin/com/squareup/workflow1/SimpleLoggingWorkflowInterceptorTest.kt
index 44eddb03f5..b3455cbf3b 100644
--- a/workflow-runtime/src/commonTest/kotlin/com/squareup/workflow1/SimpleLoggingWorkflowInterceptorTest.kt
+++ b/workflow-runtime/src/commonTest/kotlin/com/squareup/workflow1/SimpleLoggingWorkflowInterceptorTest.kt
@@ -19,7 +19,21 @@ internal class SimpleLoggingWorkflowInterceptorTest {
     interceptor.onSessionStarted(scope, TestWorkflowSession)
     scope.cancel()
 
-    assertEquals(ErrorLoggingInterceptor.EXPECTED_ERRORS, interceptor.errors)
+    // Only the first, since we don't get cancellation directly from the scope cancellation.
+    // For that we use onSessionCancelled()
+    assertEquals(listOf(ErrorLoggingInterceptor.EXPECTED_ERRORS.first()), interceptor.errors)
+  }
+
+  @Test fun onSessionCancelled_handles_logging_exceptions() {
+    val interceptor = ErrorLoggingInterceptor()
+    interceptor.onSessionCancelled<Unit, Unit, Nothing>(
+      cause = null,
+      droppedActions = emptyList(),
+      session = TestWorkflowSession
+    )
+
+    // Only the second error, since onSessionCancelled only calls logAfterMethod
+    assertEquals(listOf(ErrorLoggingInterceptor.EXPECTED_ERRORS.last()), interceptor.errors)
   }
 
   @Test fun onInitialState_handles_logging_exceptions() {
diff --git a/workflow-runtime/src/commonTest/kotlin/com/squareup/workflow1/WorkflowInterceptorTest.kt b/workflow-runtime/src/commonTest/kotlin/com/squareup/workflow1/WorkflowInterceptorTest.kt
index b9c09d349c..c6f7bce89b 100644
--- a/workflow-runtime/src/commonTest/kotlin/com/squareup/workflow1/WorkflowInterceptorTest.kt
+++ b/workflow-runtime/src/commonTest/kotlin/com/squareup/workflow1/WorkflowInterceptorTest.kt
@@ -175,6 +175,63 @@ internal class WorkflowInterceptorTest {
     intercepted.render("props", "string", RenderContext(fakeContext, workflow))
   }
 
+  @Test fun intercept_intercepts_onSessionCancelled() {
+    val recorder = RecordingWorkflowInterceptor()
+    val session = object : WorkflowSession {
+      override val identifier: WorkflowIdentifier = TestWorkflow.identifier
+      override val renderKey: String = ""
+      override val sessionId: Long = 0
+      override val parent: WorkflowSession? = null
+      override val runtimeConfig: RuntimeConfig = RuntimeConfigOptions.DEFAULT_CONFIG
+      override val workflowTracer: WorkflowTracer? = null
+      override val runtimeContext: CoroutineContext = EmptyCoroutineContext
+    }
+
+    recorder.onSessionCancelled<String, String, String>(
+      cause = null,
+      droppedActions = emptyList(),
+      session = session
+    )
+
+    // SimpleLoggingWorkflowInterceptor logs "onInstanceStarted" for onSessionCancelled
+    assertEquals(
+      listOf("END|onInstanceStarted"),
+      recorder.consumeEventNames()
+    )
+  }
+
+  @Test fun intercept_passes_dropped_actions_to_onSessionCancelled() {
+    var capturedDroppedActions: List<WorkflowAction<*, *, *>>? = null
+    val interceptor = object : WorkflowInterceptor {
+      override fun <P, S, O> onSessionCancelled(
+        cause: kotlinx.coroutines.CancellationException?,
+        droppedActions: List<WorkflowAction<P, S, O>>,
+        session: WorkflowSession
+      ) {
+        capturedDroppedActions = droppedActions
+      }
+    }
+    val session = object : WorkflowSession {
+      override val identifier: WorkflowIdentifier = TestWorkflow.identifier
+      override val renderKey: String = ""
+      override val sessionId: Long = 0
+      override val parent: WorkflowSession? = null
+      override val runtimeConfig: RuntimeConfig = RuntimeConfigOptions.DEFAULT_CONFIG
+      override val workflowTracer: WorkflowTracer? = null
+      override val runtimeContext: CoroutineContext = EmptyCoroutineContext
+    }
+    val testAction = action<String, String, String>("TestAction") { state = "modified" }
+
+    interceptor.onSessionCancelled(
+      cause = null,
+      droppedActions = listOf(testAction),
+      session = session
+    )
+
+    assertEquals(1, capturedDroppedActions!!.size)
+    assertEquals("TestAction", capturedDroppedActions!![0].debuggingName)
+  }
+
   private val Workflow<*, *, *>.session: WorkflowSession
     get() = object : WorkflowSession {
       override val identifier: WorkflowIdentifier = this@session.identifier
diff --git a/workflow-runtime/src/commonTest/kotlin/com/squareup/workflow1/internal/ChainedWorkflowInterceptorTest.kt b/workflow-runtime/src/commonTest/kotlin/com/squareup/workflow1/internal/ChainedWorkflowInterceptorTest.kt
index a8f88aca42..ad293f5aa3 100644
--- a/workflow-runtime/src/commonTest/kotlin/com/squareup/workflow1/internal/ChainedWorkflowInterceptorTest.kt
+++ b/workflow-runtime/src/commonTest/kotlin/com/squareup/workflow1/internal/ChainedWorkflowInterceptorTest.kt
@@ -70,6 +70,8 @@ internal class ChainedWorkflowInterceptorTest {
         session: WorkflowSession
       ) {
         events += "started1"
+        // We can't use onSessionCancelled because this is completed when the coroutine from
+        // launch() below finishes, so onSessionCancelled is never called by the runtime.
         workflowScope.coroutineContext[Job]!!.invokeOnCompletion {
           events += "cancelled1"
         }
diff --git a/workflow-runtime/src/commonTest/kotlin/com/squareup/workflow1/internal/WorkflowNodeTest.kt b/workflow-runtime/src/commonTest/kotlin/com/squareup/workflow1/internal/WorkflowNodeTest.kt
index bbe7d70ea7..525ff06adb 100644
--- a/workflow-runtime/src/commonTest/kotlin/com/squareup/workflow1/internal/WorkflowNodeTest.kt
+++ b/workflow-runtime/src/commonTest/kotlin/com/squareup/workflow1/internal/WorkflowNodeTest.kt
@@ -802,9 +802,14 @@ internal class WorkflowNodeTest {
       ) {
         interceptedScope = workflowScope
         interceptedSession = session
-        workflowScope.coroutineContext[Job]!!.invokeOnCompletion {
-          cancellationException = it!!
-        }
+      }
+
+      override fun <P, S, O> onSessionCancelled(
+        cause: CancellationException?,
+        droppedActions: List<WorkflowAction<P, S, O>>,
+        session: WorkflowSession
+      ) {
+        cancellationException = cause!!
       }
     }
     val workflow = Workflow.rendering<Nothing, Unit>(Unit)
@@ -843,9 +848,14 @@ internal class WorkflowNodeTest {
       ) {
         interceptedScope = workflowScope
         interceptedSession = session
-        workflowScope.coroutineContext[Job]!!.invokeOnCompletion {
-          cancellationException = it!!
-        }
+      }
+
+      override fun <P, S, O> onSessionCancelled(
+        cause: CancellationException?,
+        droppedActions: List<WorkflowAction<P, S, O>>,
+        session: WorkflowSession
+      ) {
+        cancellationException = cause!!
       }
     }
     val workflow = Workflow.rendering<Nothing, Unit>(Unit)
@@ -1182,8 +1192,8 @@ internal class WorkflowNodeTest {
     val workflow = Workflow.stateful<Unit, String, Nothing, Pair<String, Sink<String>>>(
       initialState = { "initial" },
       render = { _, renderState ->
-        renderState to actionSink.contraMap {
-          action("") { state = "$state->$it" }
+        renderState to actionSink.contraMap { value ->
+          action("") { state = "$state->$value" }
         }
       }
     )
@@ -1413,6 +1423,264 @@ internal class WorkflowNodeTest {
     assertEquals(3, third)
   }
 
+  @Test fun cancel_with_no_pending_actions_returns_empty_list() {
+    var capturedDroppedActions: List<WorkflowAction<*, *, *>>? = null
+    var capturedCause: CancellationException? = null
+    val interceptor = object : WorkflowInterceptor {
+      override fun <P, S, O> onSessionCancelled(
+        cause: CancellationException?,
+        droppedActions: List<WorkflowAction<P, S, O>>,
+        session: WorkflowSession
+      ) {
+        capturedDroppedActions = droppedActions
+        capturedCause = cause
+      }
+    }
+    val workflow = Workflow.stateless<Unit, Nothing, Unit> {}
+    val node = WorkflowNode(
+      id = workflow.id(),
+      workflow = workflow.asStatefulWorkflow(),
+      initialProps = Unit,
+      snapshot = null,
+      interceptor = interceptor,
+      baseContext = Unconfined
+    )
+
+    node.render(workflow.asStatefulWorkflow(), Unit)
+    val cause = CancellationException("test cancellation")
+    node.cancel(cause)
+
+    assertSame(cause, capturedCause)
+    assertEquals(emptyList(), capturedDroppedActions)
+  }
+
+  @Test fun cancel_with_single_pending_action_returns_that_action() {
+    var capturedDroppedActions: List<WorkflowAction<*, *, *>>? = null
+    val interceptor = object : WorkflowInterceptor {
+      override fun <P, S, O> onSessionCancelled(
+        cause: CancellationException?,
+        droppedActions: List<WorkflowAction<P, S, O>>,
+        session: WorkflowSession
+      ) {
+        capturedDroppedActions = droppedActions
+      }
+    }
+    lateinit var capturedSink: Sink<String>
+    val workflow = Workflow.stateless<Unit, String, Sink<String>> {
+      val sink = actionSink.contraMap { value: String ->
+        action("TestAction($value)") { setOutput(value) }
+      }
+      capturedSink = sink
+      sink
+    }
+    val node = WorkflowNode(
+      id = workflow.id(),
+      workflow = workflow.asStatefulWorkflow(),
+      initialProps = Unit,
+      snapshot = null,
+      interceptor = interceptor,
+      baseContext = Unconfined
+    )
+
+    node.render(workflow.asStatefulWorkflow(), Unit)
+    capturedSink.send("action1")
+
+    node.cancel()
+
+    assertEquals(1, capturedDroppedActions!!.size)
+    assertTrue(capturedDroppedActions!![0].debuggingName.startsWith("TestAction(action1)"))
+  }
+
+  @Test fun cancel_with_multiple_pending_actions_returns_all_in_order() {
+    var capturedDroppedActions: List<WorkflowAction<*, *, *>>? = null
+    val interceptor = object : WorkflowInterceptor {
+      override fun <P, S, O> onSessionCancelled(
+        cause: CancellationException?,
+        droppedActions: List<WorkflowAction<P, S, O>>,
+        session: WorkflowSession
+      ) {
+        capturedDroppedActions = droppedActions
+      }
+    }
+    lateinit var capturedSink: Sink<String>
+    val workflow = Workflow.stateless<Unit, String, Sink<String>> {
+      val sink = actionSink.contraMap { value: String ->
+        action("TestAction($value)") { setOutput(value) }
+      }
+      capturedSink = sink
+      sink
+    }
+    val node = WorkflowNode(
+      id = workflow.id(),
+      workflow = workflow.asStatefulWorkflow(),
+      initialProps = Unit,
+      snapshot = null,
+      interceptor = interceptor,
+      baseContext = Unconfined
+    )
+
+    node.render(workflow.asStatefulWorkflow(), Unit)
+    capturedSink.send("action1")
+    capturedSink.send("action2")
+    capturedSink.send("action3")
+
+    node.cancel()
+
+    assertEquals(3, capturedDroppedActions!!.size)
+    assertTrue(capturedDroppedActions!![0].debuggingName.startsWith("TestAction(action1)"))
+    assertTrue(capturedDroppedActions!![1].debuggingName.startsWith("TestAction(action2)"))
+    assertTrue(capturedDroppedActions!![2].debuggingName.startsWith("TestAction(action3)"))
+  }
+
+  @Test fun cancel_does_not_apply_pending_actions() {
+    var capturedDroppedActions: List<WorkflowAction<*, *, *>>? = null
+    var actionApplied = false
+    val interceptor = object : WorkflowInterceptor {
+      override fun <P, S, O> onSessionCancelled(
+        cause: CancellationException?,
+        droppedActions: List<WorkflowAction<P, S, O>>,
+        session: WorkflowSession
+      ) {
+        capturedDroppedActions = droppedActions
+      }
+    }
+    lateinit var capturedSink: Sink<String>
+    val workflow = Workflow.stateful<Unit, String, String, Sink<String>>(
+      initialState = { "initial" },
+      render = { _, state ->
+        val sink = actionSink.contraMap { value: String ->
+          action("TestAction($value)") {
+            actionApplied = true
+            this.state = "$state->$value"
+          }
+        }
+        capturedSink = sink
+        sink
+      }
+    )
+    val node = WorkflowNode(
+      id = workflow.id(),
+      workflow = workflow.asStatefulWorkflow(),
+      initialProps = Unit,
+      snapshot = null,
+      interceptor = interceptor,
+      baseContext = Unconfined
+    )
+
+    node.render(workflow.asStatefulWorkflow(), Unit)
+    capturedSink.send("action1")
+
+    assertFalse(actionApplied)
+    node.cancel()
+
+    // Action should not have been applied
+    assertFalse(actionApplied)
+    assertEquals(1, capturedDroppedActions!!.size)
+  }
+
+  @Test fun cancel_with_null_cause_passes_null_to_interceptor() {
+    var capturedCause: CancellationException? = CancellationException("placeholder")
+    val interceptor = object : WorkflowInterceptor {
+      override fun <P, S, O> onSessionCancelled(
+        cause: CancellationException?,
+        droppedActions: List<WorkflowAction<P, S, O>>,
+        session: WorkflowSession
+      ) {
+        capturedCause = cause
+      }
+    }
+    val workflow = Workflow.stateless<Unit, Nothing, Unit> {}
+    val node = WorkflowNode(
+      id = workflow.id(),
+      workflow = workflow.asStatefulWorkflow(),
+      initialProps = Unit,
+      snapshot = null,
+      interceptor = interceptor,
+      baseContext = Unconfined
+    )
+
+    node.render(workflow.asStatefulWorkflow(), Unit)
+    node.cancel(null)
+
+    assertNull(capturedCause)
+  }
+
+  @Test fun cancel_passes_correct_session_to_interceptor() {
+    var capturedSession: WorkflowSession? = null
+    val interceptor = object : WorkflowInterceptor {
+      override fun <P, S, O> onSessionCancelled(
+        cause: CancellationException?,
+        droppedActions: List<WorkflowAction<P, S, O>>,
+        session: WorkflowSession
+      ) {
+        capturedSession = session
+      }
+    }
+    val workflow = Workflow.stateless<Unit, Nothing, Unit> {}
+    val node = WorkflowNode(
+      id = workflow.id(key = "test-key"),
+      workflow = workflow.asStatefulWorkflow(),
+      initialProps = Unit,
+      snapshot = null,
+      interceptor = interceptor,
+      baseContext = Unconfined,
+      parent = TestSession(99)
+    )
+
+    node.render(workflow.asStatefulWorkflow(), Unit)
+    node.cancel()
+
+    assertEquals(workflow.identifier, capturedSession!!.identifier)
+    assertEquals("test-key", capturedSession!!.renderKey)
+    assertEquals(99, capturedSession!!.parent!!.sessionId)
+  }
+
+  @Test fun cancel_with_event_handler_actions_returns_them() {
+    var capturedDroppedActions: List<WorkflowAction<*, *, *>>? = null
+    val interceptor = object : WorkflowInterceptor {
+      override fun <P, S, O> onSessionCancelled(
+        cause: CancellationException?,
+        droppedActions: List<WorkflowAction<P, S, O>>,
+        session: WorkflowSession
+      ) {
+        capturedDroppedActions = droppedActions
+      }
+    }
+    val workflow = object : StringEventWorkflow() {
+      override fun initialState(
+        props: String,
+        snapshot: Snapshot?
+      ): String = props
+
+      override fun render(
+        renderProps: String,
+        renderState: String,
+        context: RenderContext<String, String, String>
+      ): (String) -> Unit {
+        return context.eventHandler("handler") { event -> setOutput(event) }
+      }
+    }
+    val node = WorkflowNode(
+      workflow.id(),
+      workflow,
+      "",
+      null,
+      context,
+      interceptor = interceptor
+    )
+
+    val eventSink = node.render(workflow, "")
+    eventSink("event1")
+    eventSink("event2")
+
+    node.cancel()
+
+    assertEquals(2, capturedDroppedActions!!.size)
+    // Event handler actions have a specific format
+    assertTrue(capturedDroppedActions!![0].debuggingName.startsWith("eH: handler"))
+    assertTrue(capturedDroppedActions!![1].debuggingName.startsWith("eH: handler"))
+  }
+
   private class TestSession(override val sessionId: Long = 0) : WorkflowSession {
     override val identifier: WorkflowIdentifier = Workflow.rendering<Nothing, Unit>(Unit).identifier
     override val renderKey: String = ""
diff --git a/workflow-testing/api/workflow-testing.api b/workflow-testing/api/workflow-testing.api
index 0c82de88a5..a4b8eea512 100644
--- a/workflow-testing/api/workflow-testing.api
+++ b/workflow-testing/api/workflow-testing.api
@@ -5,6 +5,7 @@ public final class com/squareup/workflow1/testing/RenderIdempotencyChecker : com
 	public fun onRender (Ljava/lang/Object;Ljava/lang/Object;Lcom/squareup/workflow1/BaseRenderContext;Lkotlin/jvm/functions/Function3;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)Ljava/lang/Object;
 	public fun onRenderAndSnapshot (Ljava/lang/Object;Lkotlin/jvm/functions/Function1;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)Lcom/squareup/workflow1/RenderingAndSnapshot;
 	public fun onRuntimeUpdate (Lcom/squareup/workflow1/WorkflowInterceptor$RuntimeUpdate;)V
+	public fun onSessionCancelled (Ljava/util/concurrent/CancellationException;Ljava/util/List;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)V
 	public fun onSessionStarted (Lkotlinx/coroutines/CoroutineScope;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)V
 	public fun onSnapshotState (Ljava/lang/Object;Lkotlin/jvm/functions/Function1;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)Lcom/squareup/workflow1/Snapshot;
 	public fun onSnapshotStateWithChildren (Lkotlin/jvm/functions/Function0;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)Lcom/squareup/workflow1/TreeSnapshot;
diff --git a/workflow-tracing/api/workflow-tracing.api b/workflow-tracing/api/workflow-tracing.api
index 73d9a9b6a8..23045dccdf 100644
--- a/workflow-tracing/api/workflow-tracing.api
+++ b/workflow-tracing/api/workflow-tracing.api
@@ -172,6 +172,7 @@ public final class com/squareup/workflow1/tracing/WorkflowRuntimeMonitor : com/s
 	public fun onRender (Ljava/lang/Object;Ljava/lang/Object;Lcom/squareup/workflow1/BaseRenderContext;Lkotlin/jvm/functions/Function3;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)Ljava/lang/Object;
 	public fun onRenderAndSnapshot (Ljava/lang/Object;Lkotlin/jvm/functions/Function1;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)Lcom/squareup/workflow1/RenderingAndSnapshot;
 	public fun onRuntimeUpdate (Lcom/squareup/workflow1/WorkflowInterceptor$RuntimeUpdate;)V
+	public fun onSessionCancelled (Ljava/util/concurrent/CancellationException;Ljava/util/List;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)V
 	public fun onSessionStarted (Lkotlinx/coroutines/CoroutineScope;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)V
 	public fun onSnapshotState (Ljava/lang/Object;Lkotlin/jvm/functions/Function1;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)Lcom/squareup/workflow1/Snapshot;
 	public fun onSnapshotStateWithChildren (Lkotlin/jvm/functions/Function0;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)Lcom/squareup/workflow1/TreeSnapshot;
@@ -212,6 +213,7 @@ public abstract class com/squareup/workflow1/tracing/WorkflowRuntimeTracer : com
 	public fun onRootPropsChanged (Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)V
 	public final fun onRuntimeUpdate (Lcom/squareup/workflow1/WorkflowInterceptor$RuntimeUpdate;)V
 	public fun onRuntimeUpdateEnhanced (Lcom/squareup/workflow1/WorkflowInterceptor$RuntimeUpdate;ZLcom/squareup/workflow1/tracing/ConfigSnapshot;)V
+	public final fun onSessionCancelled (Ljava/util/concurrent/CancellationException;Ljava/util/List;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)V
 	public final fun onSessionStarted (Lkotlinx/coroutines/CoroutineScope;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)V
 	public fun onSnapshotState (Ljava/lang/Object;Lkotlin/jvm/functions/Function1;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)Lcom/squareup/workflow1/Snapshot;
 	public fun onSnapshotStateWithChildren (Lkotlin/jvm/functions/Function0;Lcom/squareup/workflow1/WorkflowInterceptor$WorkflowSession;)Lcom/squareup/workflow1/TreeSnapshot;
diff --git a/workflow-tracing/src/main/java/com/squareup/workflow1/tracing/WorkflowRuntimeMonitor.kt b/workflow-tracing/src/main/java/com/squareup/workflow1/tracing/WorkflowRuntimeMonitor.kt
index 318659cca3..45d938dea9 100644
--- a/workflow-tracing/src/main/java/com/squareup/workflow1/tracing/WorkflowRuntimeMonitor.kt
+++ b/workflow-tracing/src/main/java/com/squareup/workflow1/tracing/WorkflowRuntimeMonitor.kt
@@ -29,9 +29,9 @@ import com.squareup.workflow1.tracing.RenderCause.RootPropsChanged
 import com.squareup.workflow1.tracing.RenderCause.WaitingForOutput
 import com.squareup.workflow1.tracing.WorkflowRuntimeMonitor.ActionType.CascadeAction
 import com.squareup.workflow1.tracing.WorkflowRuntimeMonitor.ActionType.QueuedAction
+import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.Job
 import kotlin.time.Duration.Companion.nanoseconds
 
 /**
@@ -84,12 +84,15 @@ public class WorkflowRuntimeMonitor(
   ) {
     onWorkflowStarted(session)
     chainedWorkflowRuntimeTracer.onWorkflowSessionStarted(workflowScope, session)
+  }
 
-    val workflowJob = workflowScope.coroutineContext[Job]!!
-    workflowJob.invokeOnCompletion {
-      onWorkflowStopped(session.sessionId)
-      chainedWorkflowRuntimeTracer.onWorkflowSessionStopped(session.sessionId)
-    }
+  override fun <P, S, O> onSessionCancelled(
+    cause: CancellationException?,
+    droppedActions: List<WorkflowAction<P, S, O>>,
+    session: WorkflowSession
+  ) {
+    onWorkflowStopped(session.sessionId)
+    chainedWorkflowRuntimeTracer.onWorkflowSessionStopped(session.sessionId)
   }
 
   /**
diff --git a/workflow-tracing/src/main/java/com/squareup/workflow1/tracing/WorkflowRuntimeTracer.kt b/workflow-tracing/src/main/java/com/squareup/workflow1/tracing/WorkflowRuntimeTracer.kt
index 43ffb89718..8edc4208d4 100644
--- a/workflow-tracing/src/main/java/com/squareup/workflow1/tracing/WorkflowRuntimeTracer.kt
+++ b/workflow-tracing/src/main/java/com/squareup/workflow1/tracing/WorkflowRuntimeTracer.kt
@@ -1,9 +1,11 @@
 package com.squareup.workflow1.tracing
 
 import androidx.collection.LongObjectMap
+import com.squareup.workflow1.WorkflowAction
 import com.squareup.workflow1.WorkflowInterceptor
 import com.squareup.workflow1.WorkflowInterceptor.RuntimeUpdate
 import com.squareup.workflow1.WorkflowInterceptor.WorkflowSession
+import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.CoroutineScope
 
 /**
@@ -97,6 +99,18 @@ public abstract class WorkflowRuntimeTracer : WorkflowInterceptor {
     super.onSessionStarted(workflowScope, session)
   }
 
+  /**
+   * Prevents [WorkflowRuntimeTracer]s from overriding this method, they should use
+   * [onWorkflowSessionStopped] instead.
+   */
+  final override fun <P, S, O> onSessionCancelled(
+    cause: CancellationException?,
+    droppedActions: List<WorkflowAction<P, S, O>>,
+    session: WorkflowSession
+  ) {
+    super.onSessionCancelled(cause, droppedActions, session)
+  }
+
   /**
    * Prevent [WorkflowRuntimeTracer] from overriding this function, as they should use
    * [onRuntimeUpdateEnhanced] instead.