diff --git a/src/window.c b/src/window.c
index 5d80e436..db37a72f 100644
--- a/src/window.c
+++ b/src/window.c
@@ -694,7 +694,7 @@ GLFWAPI float glfwGetWindowOpacity(GLFWwindow* handle)
     _GLFWwindow* window = (_GLFWwindow*) handle;
     assert(window != NULL);
 
-    _GLFW_REQUIRE_INIT_OR_RETURN(1.f);
+    _GLFW_REQUIRE_INIT_OR_RETURN(0.f);
     return _glfwPlatformGetWindowOpacity(window);
 }