diff --git a/gtk2_ardour/region_layering_order_editor.cc b/gtk2_ardour/region_layering_order_editor.cc
index 7db480d5aa..1abccade8a 100644
--- a/gtk2_ardour/region_layering_order_editor.cc
+++ b/gtk2_ardour/region_layering_order_editor.cc
@@ -1,7 +1,7 @@
 #include <gtkmm/table.h>
 #include <gtkmm/stock.h>
 #include <gtkmm/alignment.h>
-#include <ardour/region.h>
+#include "ardour/region.h"
 
 #include "gui_thread.h"
 #include "i18n.h"
diff --git a/gtk2_ardour/region_layering_order_editor.h b/gtk2_ardour/region_layering_order_editor.h
index 32d0971e5c..8c63994678 100644
--- a/gtk2_ardour/region_layering_order_editor.h
+++ b/gtk2_ardour/region_layering_order_editor.h
@@ -6,8 +6,8 @@
 #include <gtkmm/treeview.h>
 #include <gtkmm/scrolledwindow.h>
 
-#include <ardour/region.h>
-#include <ardour/playlist.h>
+#include "ardour/region.h"
+#include "ardour/playlist.h"
 
 #include "ardour_dialog.h"
 #include "audio_clock.h"
diff --git a/libs/ardour/ardour/graph.h b/libs/ardour/ardour/graph.h
index ec906455fe..56267672b7 100644
--- a/libs/ardour/ardour/graph.h
+++ b/libs/ardour/ardour/graph.h
@@ -34,8 +34,8 @@
 #include <pthread.h>
 #include <semaphore.h>
 
-#include <ardour/types.h>
-#include <ardour/session_handle.h>
+#include "ardour/types.h"
+#include "ardour/session_handle.h"
 
 namespace ARDOUR
 {
diff --git a/libs/surfaces/mackie/mackie_jog_wheel.cc b/libs/surfaces/mackie/mackie_jog_wheel.cc
index 8b01d7c89d..13ea85a7e9 100644
--- a/libs/surfaces/mackie/mackie_jog_wheel.cc
+++ b/libs/surfaces/mackie/mackie_jog_wheel.cc
@@ -1,6 +1,6 @@
 #include <cmath>
 
-#include <ardour/session.h>
+#include "ardour/session.h"
 
 #include "mackie_jog_wheel.h"