diff --git a/README.md b/README.md
index cfb748f9..1c7ced36 100644
--- a/README.md
+++ b/README.md
@@ -123,6 +123,7 @@ information on what to include when reporting a bug.
  - Added `GLFW_UNLIMITED_MOUSE_BUTTONS` input mode that allows mouse buttons beyond
    the limit of the mouse button tokens to be reported (#2423)
  - Added `glfwGetEGLConfig` function to query the `EGLConfig` of a window (#2045)
+ - Added `glfwGetGLXFBConfig` function to query the `GLXFBConfig` of a window (#1925)
  - Updated minimum CMake version to 3.16 (#2541)
  - Removed support for building with original MinGW (#2540)
  - [Win32] Removed support for Windows XP and Vista (#2505)
diff --git a/docs/news.md b/docs/news.md
index 9cbc5ffa..06a930d5 100644
--- a/docs/news.md
+++ b/docs/news.md
@@ -21,6 +21,12 @@ GLFW now provides the @ref glfwGetEGLConfig native access function for querying
 the `EGLConfig` of a window that has a `EGLSurface`.
 
 
+### GLXFBConfig native access function {#glxfbconfig}
+
+GLFW now provides the @ref glfwGetGLXFBConfig native access function for
+querying the `GLXFBConfig` of a window that has a `GLXWindow`.
+
+
 ## Caveats {#caveats}
 
 ## Deprecations {#deprecations}
@@ -47,6 +53,7 @@ actively maintained and available on many platforms.
 ### New functions {#new_functions}
 
  - @ref glfwGetEGLConfig
+ - @ref glfwGetGLXFBConfig
 
 
 ### New types {#new_types}
diff --git a/include/GLFW/glfw3native.h b/include/GLFW/glfw3native.h
index 0071d12b..8db2cfa3 100644
--- a/include/GLFW/glfw3native.h
+++ b/include/GLFW/glfw3native.h
@@ -478,6 +478,29 @@ GLFWAPI GLXContext glfwGetGLXContext(GLFWwindow* window);
  *  @ingroup native
  */
 GLFWAPI GLXWindow glfwGetGLXWindow(GLFWwindow* window);
+
+/*! @brief Retrieves the `GLXFBConfig` of the specified window's `GLXWindow`.
+ *
+ *  @param[in] window The window whose `GLXWindow` to query.
+ *  @param[out] config The `GLXFBConfig` of the window `GLXWindow`, if available.
+ *  @return `GLFW_TRUE` if successful, or `GLFW_FALSE` if an
+ *  [error](@ref error_handling) occurred.
+ *
+ *  @errors Possible errors include @ref GLFW_NOT_INITIALIZED, @ref
+ *  GLFW_NO_WINDOW_CONTEXT and @ref GLFW_PLATFORM_UNAVAILABLE.
+ *
+ *  @remark `GLXFBConfig` is an opaque type.  Unlike other GLFW functions, the
+ *  @p config out parameter is not cleared on error, as core GLX does not define
+ *  any invalid value.
+ *
+ *  @thread_safety This function may be called from any thread.  Access is not
+ *  synchronized.
+ *
+ *  @since Added in version 3.5
+ *
+ *  @ingroup native
+ */
+GLFWAPI int glfwGetGLXFBConfig(GLFWwindow* window, GLXFBConfig* config);
 #endif
 
 #if defined(GLFW_EXPOSE_NATIVE_WAYLAND)
diff --git a/src/glx_context.c b/src/glx_context.c
index a2464a9d..098c4bad 100644
--- a/src/glx_context.c
+++ b/src/glx_context.c
@@ -626,6 +626,8 @@ GLFWbool _glfwCreateContextGLX(_GLFWwindow* window,
         return GLFW_FALSE;
     }
 
+    window->context.glx.fbconfig = native;
+
     window->context.makeCurrent = makeContextCurrentGLX;
     window->context.swapBuffers = swapBuffersGLX;
     window->context.swapInterval = swapIntervalGLX;
@@ -719,5 +721,29 @@ GLFWAPI GLXWindow glfwGetGLXWindow(GLFWwindow* handle)
     return window->context.glx.window;
 }
 
+GLFWAPI int glfwGetGLXFBConfig(GLFWwindow* handle, GLXFBConfig* config)
+{
+    _GLFW_REQUIRE_INIT_OR_RETURN(GLFW_FALSE);
+
+    if (_glfw.platform.platformID != GLFW_PLATFORM_X11)
+    {
+        _glfwInputError(GLFW_PLATFORM_UNAVAILABLE, "GLX: Platform not initialized");
+        return GLFW_FALSE;
+    }
+
+    _GLFWwindow* window = (_GLFWwindow*) handle;
+    assert(window != NULL);
+    assert(config != NULL);
+
+    if (window->context.source != GLFW_NATIVE_CONTEXT_API)
+    {
+        _glfwInputError(GLFW_NO_WINDOW_CONTEXT, NULL);
+        return GLFW_FALSE;
+    }
+
+    *config = window->context.glx.fbconfig;
+    return GLFW_TRUE;
+}
+
 #endif // _GLFW_X11
 
diff --git a/src/x11_platform.h b/src/x11_platform.h
index 30326c5b..1bfeaab4 100644
--- a/src/x11_platform.h
+++ b/src/x11_platform.h
@@ -470,6 +470,7 @@ typedef struct _GLFWcontextGLX
 {
     GLXContext      handle;
     GLXWindow       window;
+    GLXFBConfig     fbconfig;
 } _GLFWcontextGLX;
 
 // GLX-specific global data