diff --git a/src/main/java/com/google/devtools/build/lib/packages/StarlarkSemanticsOptions.java b/src/main/java/com/google/devtools/build/lib/packages/StarlarkSemanticsOptions.java
index 58208a4..5ee13c1 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/StarlarkSemanticsOptions.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/StarlarkSemanticsOptions.java
@@ -90,6 +90,17 @@
       help = "If set to true, enables the APIs required to support the Android Starlark migration.")
   public boolean experimentalEnableAndroidMigrationApis;
 
+  @Option(
+      name = "experimental_google_legacy_api",
+      defaultValue = "false",
+      documentationCategory = OptionDocumentationCategory.STARLARK_SEMANTICS,
+      effectTags = {OptionEffectTag.LOADING_AND_ANALYSIS},
+      metadataTags = {OptionMetadataTag.EXPERIMENTAL},
+      help =
+          "If set to true, exposes a number of experimental pieces of Starlark build API "
+              + "pertaining to Google legacy code.")
+  public boolean experimentalGoogleLegacyApi;
+
   // This flag is declared in StarlarkSemanticsOptions instead of JavaOptions because there is no
   // way to retrieve the java configuration from the Java implementation of
   // java_common.create_provider.
@@ -573,6 +584,7 @@
         .experimentalBuildSettingApi(experimentalBuildSettingApi)
         .experimentalCcSkylarkApiEnabledPackages(experimentalCcSkylarkApiEnabledPackages)
         .experimentalEnableAndroidMigrationApis(experimentalEnableAndroidMigrationApis)
+        .experimentalGoogleLegacyApi(experimentalGoogleLegacyApi)
         .experimentalJavaCommonCreateProviderEnabledPackages(
             experimentalJavaCommonCreateProviderEnabledPackages)
         .experimentalPlatformsApi(experimentalPlatformsApi)
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/StarlarkSemantics.java b/src/main/java/com/google/devtools/build/lib/syntax/StarlarkSemantics.java
index 5d78a88..fc5ab5d 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/StarlarkSemantics.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/StarlarkSemantics.java
@@ -120,6 +120,8 @@
 
   public abstract boolean experimentalEnableAndroidMigrationApis();
 
+  public abstract boolean experimentalGoogleLegacyApi();
+
   public abstract ImmutableList<String> experimentalJavaCommonCreateProviderEnabledPackages();
 
   public abstract boolean experimentalPlatformsApi();
@@ -208,6 +210,7 @@
           .experimentalBuildSettingApi(false)
           .experimentalCcSkylarkApiEnabledPackages(ImmutableList.of())
           .experimentalEnableAndroidMigrationApis(false)
+          .experimentalGoogleLegacyApi(false)
           .experimentalJavaCommonCreateProviderEnabledPackages(ImmutableList.of())
           .experimentalPlatformsApi(false)
           .experimentalRestrictNamedParams(false)
@@ -256,6 +259,8 @@
 
     public abstract Builder experimentalEnableAndroidMigrationApis(boolean value);
 
+    public abstract Builder experimentalGoogleLegacyApi(boolean value);
+
     public abstract Builder experimentalJavaCommonCreateProviderEnabledPackages(List<String> value);
 
     public abstract Builder experimentalPlatformsApi(boolean value);
diff --git a/src/test/java/com/google/devtools/build/lib/packages/SkylarkSemanticsConsistencyTest.java b/src/test/java/com/google/devtools/build/lib/packages/SkylarkSemanticsConsistencyTest.java
index 6b6e84b..08eeec2 100644
--- a/src/test/java/com/google/devtools/build/lib/packages/SkylarkSemanticsConsistencyTest.java
+++ b/src/test/java/com/google/devtools/build/lib/packages/SkylarkSemanticsConsistencyTest.java
@@ -124,6 +124,7 @@
             + ","
             + rand.nextDouble(),
         "--experimental_enable_android_migration_apis=" + rand.nextBoolean(),
+        "--experimental_google_legacy_api=" + rand.nextBoolean(),
         "--experimental_java_common_create_provider_enabled_packages="
             + rand.nextDouble()
             + ","
@@ -175,6 +176,7 @@
         .experimentalCcSkylarkApiEnabledPackages(
             ImmutableList.of(String.valueOf(rand.nextDouble()), String.valueOf(rand.nextDouble())))
         .experimentalEnableAndroidMigrationApis(rand.nextBoolean())
+        .experimentalGoogleLegacyApi(rand.nextBoolean())
         .experimentalJavaCommonCreateProviderEnabledPackages(
             ImmutableList.of(String.valueOf(rand.nextDouble()), String.valueOf(rand.nextDouble())))
         .experimentalPlatformsApi(rand.nextBoolean())