diff --git a/packages/core/android/build.gradle b/packages/core/android/build.gradle
index 1b3238fa2..93163231a 100644
--- a/packages/core/android/build.gradle
+++ b/packages/core/android/build.gradle
@@ -36,7 +36,28 @@ apply plugin: 'com.android.library'
 if (isNewArchitectureEnabled()) {
   apply plugin: 'com.facebook.react'
 }
-apply plugin: 'kotlin-android'
+// Android Gradle Plugin 9 ships built-in Kotlin support and applies the Kotlin
+// plugin itself. Applying it a second time fails the configuration phase with
+// "Cannot add extension with name 'kotlin'". Apply it only when AGP is not
+// providing Kotlin: AGP 8 and older; AGP 9 only when android.builtInKotlin=false (AGP 10 always provides Kotlin).
+def shouldApplyKotlinPlugin() {
+  def agpMajor = com.android.Version.ANDROID_GRADLE_PLUGIN_VERSION.tokenize('.')[0].toInteger()
+  if (agpMajor <= 8) {
+    return true
+  }
+  // AGP 10 removes the opt-out: built-in Kotlin is always active there.
+  if (agpMajor >= 10) {
+    return false
+  }
+  def propertyVal = providers.gradleProperty("android.builtInKotlin").orNull
+  def builtInKotlinEnabled = propertyVal != null ? propertyVal.toBoolean() : true
+  return !builtInKotlinEnabled
+}
+
+if (shouldApplyKotlinPlugin()) {
+  apply plugin: 'kotlin-android'
+}
+
 apply plugin: 'org.jlleitschuh.gradle.ktlint'
 
 
diff --git a/packages/internal-testing-tools/android/build.gradle b/packages/internal-testing-tools/android/build.gradle
index 276d3e508..f2b211975 100644
--- a/packages/internal-testing-tools/android/build.gradle
+++ b/packages/internal-testing-tools/android/build.gradle
@@ -31,7 +31,28 @@ apply plugin: 'com.android.library'
 if (isNewArchitectureEnabled()) {
   apply plugin: 'com.facebook.react'
 }
-apply plugin: 'kotlin-android'
+// Android Gradle Plugin 9 ships built-in Kotlin support and applies the Kotlin
+// plugin itself. Applying it a second time fails the configuration phase with
+// "Cannot add extension with name 'kotlin'". Apply it only when AGP is not
+// providing Kotlin: AGP 8 and older; AGP 9 only when android.builtInKotlin=false (AGP 10 always provides Kotlin).
+def shouldApplyKotlinPlugin() {
+  def agpMajor = com.android.Version.ANDROID_GRADLE_PLUGIN_VERSION.tokenize('.')[0].toInteger()
+  if (agpMajor <= 8) {
+    return true
+  }
+  // AGP 10 removes the opt-out: built-in Kotlin is always active there.
+  if (agpMajor >= 10) {
+    return false
+  }
+  def propertyVal = providers.gradleProperty("android.builtInKotlin").orNull
+  def builtInKotlinEnabled = propertyVal != null ? propertyVal.toBoolean() : true
+  return !builtInKotlinEnabled
+}
+
+if (shouldApplyKotlinPlugin()) {
+  apply plugin: 'kotlin-android'
+}
+
 apply plugin: 'org.jlleitschuh.gradle.ktlint'
 
 /**
diff --git a/packages/react-native-session-replay/android/build.gradle b/packages/react-native-session-replay/android/build.gradle
index f9f1b3da3..34a278072 100644
--- a/packages/react-native-session-replay/android/build.gradle
+++ b/packages/react-native-session-replay/android/build.gradle
@@ -34,7 +34,28 @@ apply plugin: 'com.android.library'
 if (isNewArchitectureEnabled()) {
   apply plugin: 'com.facebook.react'
 }
-apply plugin: 'kotlin-android'
+// Android Gradle Plugin 9 ships built-in Kotlin support and applies the Kotlin
+// plugin itself. Applying it a second time fails the configuration phase with
+// "Cannot add extension with name 'kotlin'". Apply it only when AGP is not
+// providing Kotlin: AGP 8 and older; AGP 9 only when android.builtInKotlin=false (AGP 10 always provides Kotlin).
+def shouldApplyKotlinPlugin() {
+  def agpMajor = com.android.Version.ANDROID_GRADLE_PLUGIN_VERSION.tokenize('.')[0].toInteger()
+  if (agpMajor <= 8) {
+    return true
+  }
+  // AGP 10 removes the opt-out: built-in Kotlin is always active there.
+  if (agpMajor >= 10) {
+    return false
+  }
+  def propertyVal = providers.gradleProperty("android.builtInKotlin").orNull
+  def builtInKotlinEnabled = propertyVal != null ? propertyVal.toBoolean() : true
+  return !builtInKotlinEnabled
+}
+
+if (shouldApplyKotlinPlugin()) {
+  apply plugin: 'kotlin-android'
+}
+
 apply plugin: 'org.jlleitschuh.gradle.ktlint'
 
 /**
diff --git a/packages/react-native-webview/android/build.gradle b/packages/react-native-webview/android/build.gradle
index e145fb2cd..6f165cf20 100644
--- a/packages/react-native-webview/android/build.gradle
+++ b/packages/react-native-webview/android/build.gradle
@@ -32,7 +32,28 @@ apply plugin: 'com.android.library'
 if (isNewArchitectureEnabled()) {
   apply plugin: 'com.facebook.react'
 }
-apply plugin: 'kotlin-android'
+// Android Gradle Plugin 9 ships built-in Kotlin support and applies the Kotlin
+// plugin itself. Applying it a second time fails the configuration phase with
+// "Cannot add extension with name 'kotlin'". Apply it only when AGP is not
+// providing Kotlin: AGP 8 and older; AGP 9 only when android.builtInKotlin=false (AGP 10 always provides Kotlin).
+def shouldApplyKotlinPlugin() {
+  def agpMajor = com.android.Version.ANDROID_GRADLE_PLUGIN_VERSION.tokenize('.')[0].toInteger()
+  if (agpMajor <= 8) {
+    return true
+  }
+  // AGP 10 removes the opt-out: built-in Kotlin is always active there.
+  if (agpMajor >= 10) {
+    return false
+  }
+  def propertyVal = providers.gradleProperty("android.builtInKotlin").orNull
+  def builtInKotlinEnabled = propertyVal != null ? propertyVal.toBoolean() : true
+  return !builtInKotlinEnabled
+}
+
+if (shouldApplyKotlinPlugin()) {
+  apply plugin: 'kotlin-android'
+}
+
 apply plugin: 'org.jlleitschuh.gradle.ktlint'
 apply plugin: "io.gitlab.arturbosch.detekt"