diff --git a/js/src/moz.build b/js/src/moz.build
index d915f16e1e5a..4e3e7abf3f2c 100755
--- a/js/src/moz.build
+++ b/js/src/moz.build
@@ -547,6 +547,7 @@ if CONFIG["MOZ_VTUNE"]:
     ]
     SOURCES["vtune/ittnotify_static.c"].flags += [
         "-Wno-varargs",
+        "-Wno-sign-compare",
         "-Wno-unknown-pragmas",
     ]
     if CONFIG["CC_TYPE"] == "gcc":
diff --git a/js/src/zydis/moz.build b/js/src/zydis/moz.build
index 7231f290c56e..7d486e4b68a2 100644
--- a/js/src/zydis/moz.build
+++ b/js/src/zydis/moz.build
@@ -38,3 +38,6 @@ if CONFIG['JS_CODEGEN_X64'] or CONFIG['JS_CODEGEN_X86']:
         'Zydis/ZydisString.c',
         'ZydisAPI.cpp',
     ]
+
+    # Suppress warnings in third-party code.
+    SOURCES['Zydis/SharedData.c'].flags += ['-Wno-sign-compare']