diff --git a/cc/compiler.go b/cc/compiler.go
index 396ec88..a6f623f 100644
--- a/cc/compiler.go
+++ b/cc/compiler.go
@@ -437,18 +437,20 @@
 		flags.Global.CommonFlags = append(flags.Global.CommonFlags, "-D__ANDROID_VNDK__")
 		if ctx.inVendor() {
 			flags.Global.CommonFlags = append(flags.Global.CommonFlags, "-D__ANDROID_VENDOR__")
-
-			vendorApiLevel := ctx.Config().VendorApiLevel()
-			if vendorApiLevel == "" {
-				// TODO(b/314036847): This is a fallback for UDC targets.
-				// This must be a build failure when UDC is no longer built
-				// from this source tree.
-				vendorApiLevel = ctx.Config().PlatformSdkVersion().String()
-			}
-			flags.Global.CommonFlags = append(flags.Global.CommonFlags, "-D__ANDROID_VENDOR_API__="+vendorApiLevel)
 		} else if ctx.inProduct() {
 			flags.Global.CommonFlags = append(flags.Global.CommonFlags, "-D__ANDROID_PRODUCT__")
 		}
+
+		// Define __ANDROID_VENDOR_API__ for both product and vendor variants
+		// because they both use the same LLNDK libraries.
+		vendorApiLevel := ctx.Config().VendorApiLevel()
+		if vendorApiLevel == "" {
+			// TODO(b/314036847): This is a fallback for UDC targets.
+			// This must be a build failure when UDC is no longer built
+			// from this source tree.
+			vendorApiLevel = ctx.Config().PlatformSdkVersion().String()
+		}
+		flags.Global.CommonFlags = append(flags.Global.CommonFlags, "-D__ANDROID_VENDOR_API__="+vendorApiLevel)
 	}
 
 	if ctx.inRecovery() {
diff --git a/rust/bindgen.go b/rust/bindgen.go
index 31aa137..abb5181 100644
--- a/rust/bindgen.go
+++ b/rust/bindgen.go
@@ -198,18 +198,20 @@
 		cflags = append(cflags, "-D__ANDROID_VNDK__")
 		if ctx.RustModule().InVendor() {
 			cflags = append(cflags, "-D__ANDROID_VENDOR__")
-
-			vendorApiLevel := ctx.Config().VendorApiLevel()
-			if vendorApiLevel == "" {
-				// TODO(b/314036847): This is a fallback for UDC targets.
-				// This must be a build failure when UDC is no longer built
-				// from this source tree.
-				vendorApiLevel = ctx.Config().PlatformSdkVersion().String()
-			}
-			cflags = append(cflags, "-D__ANDROID_VENDOR_API__="+vendorApiLevel)
 		} else if ctx.RustModule().InProduct() {
 			cflags = append(cflags, "-D__ANDROID_PRODUCT__")
 		}
+
+		// Define __ANDROID_VENDOR_API__ for both product and vendor variants
+		// because they both use the same LLNDK libraries.
+		vendorApiLevel := ctx.Config().VendorApiLevel()
+		if vendorApiLevel == "" {
+			// TODO(b/314036847): This is a fallback for UDC targets.
+			// This must be a build failure when UDC is no longer built
+			// from this source tree.
+			vendorApiLevel = ctx.Config().PlatformSdkVersion().String()
+		}
+		cflags = append(cflags, "-D__ANDROID_VENDOR_API__="+vendorApiLevel)
 	}
 
 	if ctx.RustModule().InRecovery() {