diff --git a/toolkit/library/gtest/rust/moz.build b/toolkit/library/gtest/rust/moz.build
index 6fe3f8931bc2..26ba750e09f3 100644
--- a/toolkit/library/gtest/rust/moz.build
+++ b/toolkit/library/gtest/rust/moz.build
@@ -14,4 +14,4 @@ if CONFIG['MOZ_STYLO']:
 if CONFIG['MOZ_ENABLE_WEBRENDER']:
     features += ['quantum_render']
 
-RustLibrary('gkrust-gtest', features)
+RustLibrary('gkrust-gtest', features, '../..')
diff --git a/toolkit/library/rust/moz.build b/toolkit/library/rust/moz.build
index a5cec1fbbf19..069a8d4ecde7 100644
--- a/toolkit/library/rust/moz.build
+++ b/toolkit/library/rust/moz.build
@@ -14,4 +14,4 @@ if CONFIG['MOZ_STYLO']:
 if CONFIG['MOZ_ENABLE_WEBRENDER']:
     features += ['quantum_render']
 
-RustLibrary('gkrust', features)
+RustLibrary('gkrust', features, '..')