diff --git a/docs/build.dox b/docs/build.dox
index 86ec1e5f..60a1df63 100644
--- a/docs/build.dox
+++ b/docs/build.dox
@@ -50,7 +50,9 @@ header that the GLFW header includes and GLEW will work as expected.
 @subsection build_macros GLFW header option macros
 
 These macros may be defined before the inclusion of the GLFW header and affect
-how that header behaves.
+the behavior of the header.  Note that GLFW does not provide any of the OpenGL
+or OpenGL ES headers mentioned below.  These are provided by your development
+environment or your OpenGL or OpenGL ES SDK.
 
 `GLFW_INCLUDE_GLCOREARB` makes the header include the modern `GL/glcorearb.h`
 header (`OpenGL/gl3.h` on OS X) instead of the regular OpenGL header.