diff --git a/libraries/SITL/SIM_Frame.h b/libraries/SITL/SIM_Frame.h
index 7d8bfff435..6e2d0f1cff 100644
--- a/libraries/SITL/SIM_Frame.h
+++ b/libraries/SITL/SIM_Frame.h
@@ -22,7 +22,7 @@
 #include "SIM_Aircraft.h"
 #include "SIM_Motor.h"
 
-using namespace SITL;
+namespace SITL {
 
 /*
   class to describe a multicopter frame type
@@ -58,3 +58,4 @@ public:
     float mass;
     uint8_t motor_offset;
 };
+}
diff --git a/libraries/SITL/SIM_Motor.h b/libraries/SITL/SIM_Motor.h
index 8171d47bd4..46a956e45e 100644
--- a/libraries/SITL/SIM_Motor.h
+++ b/libraries/SITL/SIM_Motor.h
@@ -21,7 +21,7 @@
 
 #include "SIM_Aircraft.h"
 
-using namespace SITL;
+namespace SITL {
 
 /*
   class to describe a motor position
@@ -70,3 +70,4 @@ public:
                           Vector3f &rot_accel, // rad/sec
                           Vector3f &body_thrust) const; // Z is down
 };
+}
diff --git a/libraries/SITL/SIM_Multicopter.h b/libraries/SITL/SIM_Multicopter.h
index 7cbaf9ff57..a24dc59e71 100644
--- a/libraries/SITL/SIM_Multicopter.h
+++ b/libraries/SITL/SIM_Multicopter.h
@@ -23,7 +23,7 @@
 #include "SIM_Motor.h"
 #include "SIM_Frame.h"
 
-using namespace SITL;
+namespace SITL {
 
 /*
   a multicopter simulator
@@ -46,3 +46,4 @@ protected:
     Frame *frame;
 };
 
+}