diff --git a/.changes/5d0ee9f1-66d0-4654-9014-ef8ebea8ce17.json b/.changes/5d0ee9f1-66d0-4654-9014-ef8ebea8ce17.json
new file mode 100644
index 00000000000..757fce24c6a
--- /dev/null
+++ b/.changes/5d0ee9f1-66d0-4654-9014-ef8ebea8ce17.json
@@ -0,0 +1,5 @@
+{
+    "id": "5d0ee9f1-66d0-4654-9014-ef8ebea8ce17",
+    "type": "misc",
+    "description": "Upgrade smithy-kotlin version."
+}
\ No newline at end of file
diff --git a/gradle.properties b/gradle.properties
index afd35728b9e..3c66a329f2e 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -9,10 +9,10 @@ org.gradle.jvmargs=-Xmx6g -XX:MaxMetaspaceSize=2G
 sdkVersion=0.17.7-SNAPSHOT
 
 # codegen
-smithyVersion=1.23.0
+smithyVersion=1.25.2
 smithyGradleVersion=0.6.0
 # smithy-kotlin codegen and runtime are versioned together
-smithyKotlinVersion=0.12.7
+smithyKotlinVersion=0.12.8
 
 # kotlin
 kotlinVersion=1.7.10