diff --git a/include/osg/GLDefines b/include/osg/GLDefines
index 5f903375c..f89cf386f 100644
--- a/include/osg/GLDefines
+++ b/include/osg/GLDefines
@@ -183,6 +183,10 @@ typedef char GLchar;
 #define GL_GEOMETRY_OUTPUT_TYPE_EXT             0x8DDC
 #define GL_MAX_GEOMETRY_VARYING_COMPONENTS_EXT  0x8DDD
 #define GL_MAX_VERTEX_VARYING_COMPONENTS_EXT    0x8DDE
+#define GL_LINES_ADJACENCY_EXT                  0x000A
+#define GL_LINE_STRIP_ADJACENCY_EXT             0x000B
+#define GL_TRIANGLES_ADJACENCY_EXT              0x000C
+#define GL_TRIANGLE_STRIP_ADJACENCY_EXT         0x000D
 #endif
 
 #ifndef GL_VERSION_3_2