diff --git a/packages/flutter_tools/gradle/src/main/kotlin/FlutterPlugin.kt b/packages/flutter_tools/gradle/src/main/kotlin/FlutterPlugin.kt
index a0f3046..9dc036d 100644
--- a/packages/flutter_tools/gradle/src/main/kotlin/FlutterPlugin.kt
+++ b/packages/flutter_tools/gradle/src/main/kotlin/FlutterPlugin.kt
@@ -265,15 +265,18 @@
                     // Enables resource shrinking, which is performed by the Android Gradle plugin.
                     // The resource shrinker can't be used for libraries.
                     isShrinkResources = FlutterPluginUtils.isBuiltAsApp(project)
-                    // Fallback to `android/app/proguard-rules.pro`.
-                    // This way, custom Proguard rules can be configured as needed.
                     proguardFiles(
                         FlutterPluginUtils
                             .getAndroidExtension(project)
                             .getDefaultProguardFile("proguard-android-optimize.txt"),
-                        flutterProguardRules,
-                        "proguard-rules.pro"
+                        flutterProguardRules
                     )
+
+                    // Optionally adds custom Proguard rules as needed from `android/app/proguard-rules.pro`.
+                    // Starting AGP 9.0 Proguard files must exist to be added to the configuration.
+                    if (File("${project.projectDir}/proguard-rules.pro").exists()) {
+                        proguardFile("proguard-rules.pro")
+                    }
                 }
             }
         }