diff --git a/source/blender/windowmanager/intern/wm_gesture_ops.cc b/source/blender/windowmanager/intern/wm_gesture_ops.cc
index 91c762fafbe..4ad5a619756 100644
--- a/source/blender/windowmanager/intern/wm_gesture_ops.cc
+++ b/source/blender/windowmanager/intern/wm_gesture_ops.cc
@@ -1052,6 +1052,22 @@ static void wm_gesture_straightline_do_angle_snap(rcti *rect, float snap_angle)
 
   rect->xmax = int(line_snapped_end[0]);
   rect->ymax = int(line_snapped_end[1]);
+
+  /* Check whether `angle_snapped` is a multiple of 45 degrees, if so ensure X and Y directions
+   * are the same length (there could be an off-by-one due to rounding error). */
+  const float fract_45 = fractf(angle_snapped / DEG2RADF(45.0f));
+  const float fract_90 = fractf(angle_snapped / DEG2RADF(90.0f));
+  /* Check if it's a multiple of 45 but not 90 degrees. */
+  if ((compare_ff(fract_45, 0.0f, 1e-6) || compare_ff(fabsf(fract_45), 1.0f, 1e-6)) &&
+      (!(compare_ff(fract_90, 0.0f, 1e-6) || compare_ff(fabsf(fract_90), 1.0f, 1e-6))))
+  {
+    int xlen = abs(rect->xmax - rect->xmin);
+    int ylen = rect->ymax - rect->ymin;
+    if (abs(ylen) != xlen) {
+      ylen = xlen * (ylen >= 0 ? 1 : -1);
+      rect->ymax = rect->ymin + ylen;
+    }
+  }
 }
 
 int WM_gesture_straightline_modal(bContext *C, wmOperator *op, const wmEvent *event)