diff --git a/reactor-test/src/main/java/reactor/test/DefaultStepVerifierBuilder.java b/reactor-test/src/main/java/reactor/test/DefaultStepVerifierBuilder.java
index 1692e50462..87fcc00165 100644
--- a/reactor-test/src/main/java/reactor/test/DefaultStepVerifierBuilder.java
+++ b/reactor-test/src/main/java/reactor/test/DefaultStepVerifierBuilder.java
@@ -34,6 +34,8 @@
 import java.util.concurrent.atomic.AtomicLongFieldUpdater;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
 import java.util.function.BiFunction;
 import java.util.function.BooleanSupplier;
 import java.util.function.Consumer;
@@ -644,6 +646,9 @@ interface Event<T> {
 
 	final static class DefaultStepVerifier<T> implements StepVerifier {
 
+		/** A global lock that is used to make withVirtualTime calls mutually exclusive */
+		private static final Lock vtsLock = new ReentrantLock(true);
+
 		private final DefaultStepVerifierBuilder<T> parent;
 		private final int requestedFusionMode;
 		private final int expectedFusionMode;
@@ -701,6 +706,7 @@ public Duration verify(Duration duration) {
 			if (parent.sourceSupplier != null) {
 				VirtualTimeScheduler vts = null;
 				if (parent.vtsLookup != null) {
+					vtsLock.lock(); //wait for other virtualtime verifies to finish
 					vts = parent.vtsLookup.get();
 					//this works even for the default case where StepVerifier has created
 					// a vts through enable(false), because the CURRENT will already be that vts
@@ -730,6 +736,7 @@ public Duration verify(Duration duration) {
 						//explicitly reset the factory, rather than rely on vts shutdown doing so
 						// because it could have been eagerly shut down in a test.
 						VirtualTimeScheduler.reset();
+						vtsLock.unlock();
 					}
 				}
 			} else {
diff --git a/reactor-test/src/test/java/reactor/test/StepVerifierTests.java b/reactor-test/src/test/java/reactor/test/StepVerifierTests.java
index 54f11858b6..cb913b575c 100644
--- a/reactor-test/src/test/java/reactor/test/StepVerifierTests.java
+++ b/reactor-test/src/test/java/reactor/test/StepVerifierTests.java
@@ -21,6 +21,9 @@
 import java.util.Collections;
 import java.util.Date;
 import java.util.List;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -1893,4 +1896,38 @@ public void assertNextWithSubscribeOnJust() {
 						            .thenCancel()
 								::verify);
 	}
+
+	@Test
+	public void parallelVerifyWithVtsMutuallyExclusive() {
+		ExecutorService executorService = Executors.newFixedThreadPool(2);
+		for (int i = 0; i < 10; i++) {
+			Future<Duration> ex1 = executorService.submit(() -> StepVerifier
+					.withVirtualTime(() -> Flux.just("A", "B", "C")
+					                           .delaySequence(Duration.ofMillis(100))
+					)
+					.then(() -> {
+						try {
+							Thread.sleep(100);
+						}
+						catch (InterruptedException e) {
+							e.printStackTrace();
+						}
+					})
+					.thenAwait(Duration.ofMillis(100))
+					.expectNextCount(3)
+					.verifyComplete());
+
+			Future<Duration> ex2 = executorService.submit(() -> StepVerifier
+					.withVirtualTime(() -> Flux.just(1, 2, 3)
+					                           .delaySequence(Duration.ofMillis(100))
+					)
+					.thenAwait(Duration.ofMillis(100))
+					.expectNextCount(3)
+					.expectComplete()
+					.verify());
+
+			assertThatCode(ex1::get).as("execution 1 in iteration #" + i).doesNotThrowAnyException();
+			assertThatCode(ex2::get).as("execution 2 in iteration #" + i).doesNotThrowAnyException();
+		}
+	}
 }
\ No newline at end of file