diff --git a/cogl/cogl-framebuffer.c b/cogl/cogl-framebuffer.c
index 7acf1edbd..83b1b3a9a 100644
--- a/cogl/cogl-framebuffer.c
+++ b/cogl/cogl-framebuffer.c
@@ -2808,7 +2808,7 @@ cogl_framebuffer_get_modelview_matrix (CoglFramebuffer *framebuffer,
 
 void
 cogl_framebuffer_set_modelview_matrix (CoglFramebuffer *framebuffer,
-                                       CoglMatrix *matrix)
+                                       const CoglMatrix *matrix)
 {
   CoglMatrixStack *modelview_stack =
     _cogl_framebuffer_get_modelview_stack (framebuffer);
@@ -2833,7 +2833,7 @@ cogl_framebuffer_get_projection_matrix (CoglFramebuffer *framebuffer,
 
 void
 cogl_framebuffer_set_projection_matrix (CoglFramebuffer *framebuffer,
-                                        CoglMatrix *matrix)
+                                        const CoglMatrix *matrix)
 {
   CoglMatrixStack *projection_stack =
     _cogl_framebuffer_get_projection_stack (framebuffer);
diff --git a/cogl/cogl-framebuffer.h b/cogl/cogl-framebuffer.h
index 44510e62a..d72845f54 100644
--- a/cogl/cogl-framebuffer.h
+++ b/cogl/cogl-framebuffer.h
@@ -425,7 +425,7 @@ cogl_framebuffer_get_modelview_matrix (CoglFramebuffer *framebuffer,
  */
 void
 cogl_framebuffer_set_modelview_matrix (CoglFramebuffer *framebuffer,
-                                       CoglMatrix *matrix);
+                                       const CoglMatrix *matrix);
 
 /**
  * cogl_framebuffer_perspective:
@@ -539,7 +539,7 @@ cogl_framebuffer_get_projection_matrix (CoglFramebuffer *framebuffer,
  */
 void
 cogl_framebuffer_set_projection_matrix (CoglFramebuffer *framebuffer,
-                                        CoglMatrix *matrix);
+                                        const CoglMatrix *matrix);
 
 /**
  * cogl_framebuffer_push_scissor_clip: