diff --git a/gtk2_ardour/editor.h b/gtk2_ardour/editor.h
index 428b1889e6..7d79d7ef3e 100644
--- a/gtk2_ardour/editor.h
+++ b/gtk2_ardour/editor.h
@@ -25,7 +25,6 @@
 #include <set>
 #include <string>
 #include <sys/time.h>
-#include <bitset>
 
 #include <boost/optional.hpp>
 
diff --git a/gtk2_ardour/editor_drag.h b/gtk2_ardour/editor_drag.h
index ce8a1370f4..740f6e42c9 100644
--- a/gtk2_ardour/editor_drag.h
+++ b/gtk2_ardour/editor_drag.h
@@ -24,7 +24,6 @@
 
 #include <gdk/gdk.h>
 #include <stdint.h>
-#include <bitset>
 
 #include "ardour/types.h"
 
diff --git a/libs/ardour/ardour/midi_state_tracker.h b/libs/ardour/ardour/midi_state_tracker.h
index f6acb88f23..9848d55da9 100644
--- a/libs/ardour/ardour/midi_state_tracker.h
+++ b/libs/ardour/ardour/midi_state_tracker.h
@@ -20,7 +20,6 @@
 #ifndef __ardour_midi_state_tracker_h__
 #define __ardour_midi_state_tracker_h__
 
-#include <bitset>
 #include "ardour/midi_buffer.h"
 
 namespace Evoral {