diff --git a/README.md b/README.md
index c7904c19..8066c6cf 100644
--- a/README.md
+++ b/README.md
@@ -157,7 +157,8 @@ GLFW bundles a number of dependencies in the `deps/` directory.
  - [X11] Bugfix: Window frame interactions were reported as focus events
  - [X11] Bugfix: Workaround for legacy Compiz caused flickering during resize
  - [X11] Bugfix: The name pointer of joysticks were not cleared on disconnection
- - [X11] Bugfix: Video mode dimensions were not rotated to match the CRTC
+ - [X11] Bugfix: Video mode resolutions and monitor physical sizes were not
+                 corrected for rotated CRTCs
  - [X11] Bugfix: Unicode character input ignored dead keys
  - [X11] Bugfix: X-axis scroll offsets were inverted
  - [X11] Bugfix: Full screen override redirect windows were not always
diff --git a/src/x11_monitor.c b/src/x11_monitor.c
index fb6b0ef6..6265070f 100644
--- a/src/x11_monitor.c
+++ b/src/x11_monitor.c
@@ -224,6 +224,7 @@ _GLFWmonitor** _glfwPlatformGetMonitors(int* count)
 
             for (j = 0;  j < ci->noutput;  j++)
             {
+                int widthMM, heightMM;
                 XRROutputInfo* oi = XRRGetOutputInfo(_glfw.x11.display,
                                                      sr, ci->outputs[j]);
                 if (oi->connection != RR_Connected)
@@ -238,10 +239,18 @@ _GLFWmonitor** _glfwPlatformGetMonitors(int* count)
                     monitors = realloc(monitors, sizeof(_GLFWmonitor*) * size);
                 }
 
-                monitors[found] = _glfwAllocMonitor(oi->name,
-                                                    oi->mm_width,
-                                                    oi->mm_height);
+                if (ci->rotation == RR_Rotate_90 || ci->rotation == RR_Rotate_270)
+                {
+                    widthMM  = oi->mm_height;
+                    heightMM = oi->mm_width;
+                }
+                else
+                {
+                    widthMM  = oi->mm_width;
+                    heightMM = oi->mm_height;
+                }
 
+                monitors[found] = _glfwAllocMonitor(oi->name, widthMM, heightMM);
                 monitors[found]->x11.output = ci->outputs[j];
                 monitors[found]->x11.crtc   = oi->crtc;