diff --git a/thread/service/Android.bp b/thread/service/Android.bp
index bd265e6..35ae3c2 100644
--- a/thread/service/Android.bp
+++ b/thread/service/Android.bp
@@ -43,6 +43,9 @@
         "ot-daemon-aidl-java",
     ],
     apex_available: ["com.android.tethering"],
+    optimize: {
+        proguard_flags_files: ["proguard.flags"],
+    },
 }
 
 cc_library_shared {