diff --git a/unittests/unit/test_Signal.cpp b/unittests/unit/test_Signal.cpp
index 0cc1603a18cbd..6be0c39f3244c 100644
--- a/unittests/unit/test_Signal.cpp
+++ b/unittests/unit/test_Signal.cpp
@@ -139,8 +139,8 @@ TEST(Signal, NonStaticMemberFunction)
   signal2.connect(&Viewer::onSignal2Static);
 
   // Connect non-static member function
-  using placeholders::_1;
-  using placeholders::_2;
+  using std::placeholders::_1;
+  using std::placeholders::_2;
   signal1.connect(bind(&Viewer::onSignal1, &viewer, _1));
   signal2.connect(bind(&Viewer::onSignal2, &viewer, _1, _2));