diff --git a/libretro-test-gl/libretro-test.c b/libretro-test-gl/libretro-test.c
index 170bb154fc..58b8ce3a77 100644
--- a/libretro-test-gl/libretro-test.c
+++ b/libretro-test-gl/libretro-test.c
@@ -119,6 +119,9 @@ static const char *vertex_shader[] = {
 };
 
 static const char *fragment_shader[] = {
+   "#ifdef GL_ES\n",
+   "precision mediump float;\n",
+   "#endif\n",
    "varying vec4 color;",
    "void main() {",
    "  gl_FragColor = color;",