diff --git a/source/blender/compositor/realtime_compositor/cached_resources/COM_cached_mask.hh b/source/blender/compositor/realtime_compositor/cached_resources/COM_cached_mask.hh
index 3a6482abf42..f512b432682 100644
--- a/source/blender/compositor/realtime_compositor/cached_resources/COM_cached_mask.hh
+++ b/source/blender/compositor/realtime_compositor/cached_resources/COM_cached_mask.hh
@@ -28,11 +28,16 @@ class Context;
 class CachedMaskKey {
  public:
   int2 size;
+  float aspect_ratio;
   bool use_feather;
   int motion_blur_samples;
   float motion_blur_shutter;
 
-  CachedMaskKey(int2 size, bool use_feather, int motion_blur_samples, float motion_blur_shutter);
+  CachedMaskKey(int2 size,
+                float aspect_ratio,
+                bool use_feather,
+                int motion_blur_samples,
+                float motion_blur_shutter);
 
   uint64_t hash() const;
 };
@@ -53,6 +58,7 @@ class CachedMask : public CachedResource {
              Mask *mask,
              int2 size,
              int frame,
+             float aspect_ratio,
              bool use_feather,
              int motion_blur_samples,
              float motion_blur_shutter);
@@ -81,6 +87,7 @@ class CachedMaskContainer : CachedResourceContainer {
   CachedMask &get(Context &context,
                   Mask *mask,
                   int2 size,
+                  float aspect_ratio,
                   bool use_feather,
                   int motion_blur_samples,
                   float motion_blur_shutter);
diff --git a/source/blender/compositor/realtime_compositor/cached_resources/intern/cached_mask.cc b/source/blender/compositor/realtime_compositor/cached_resources/intern/cached_mask.cc
index dfca915ea4d..3c9b8bb4420 100644
--- a/source/blender/compositor/realtime_compositor/cached_resources/intern/cached_mask.cc
+++ b/source/blender/compositor/realtime_compositor/cached_resources/intern/cached_mask.cc
@@ -31,10 +31,12 @@ namespace blender::realtime_compositor {
  */
 
 CachedMaskKey::CachedMaskKey(int2 size,
+                             float aspect_ratio,
                              bool use_feather,
                              int motion_blur_samples,
                              float motion_blur_shutter)
     : size(size),
+      aspect_ratio(aspect_ratio),
       use_feather(use_feather),
       motion_blur_samples(motion_blur_samples),
       motion_blur_shutter(motion_blur_shutter)
@@ -43,12 +45,13 @@ CachedMaskKey::CachedMaskKey(int2 size,
 
 uint64_t CachedMaskKey::hash() const
 {
-  return get_default_hash_4(size, use_feather, motion_blur_samples, motion_blur_shutter);
+  return get_default_hash_4(
+      size, use_feather, motion_blur_samples, float2(motion_blur_shutter, aspect_ratio));
 }
 
 bool operator==(const CachedMaskKey &a, const CachedMaskKey &b)
 {
-  return a.size == b.size && a.use_feather == b.use_feather &&
+  return a.size == b.size && a.aspect_ratio == b.aspect_ratio && a.use_feather == b.use_feather &&
          a.motion_blur_samples == b.motion_blur_samples &&
          a.motion_blur_shutter == b.motion_blur_shutter;
 }
@@ -104,6 +107,7 @@ CachedMask::CachedMask(Context &context,
                        Mask *mask,
                        int2 size,
                        int frame,
+                       float aspect_ratio,
                        bool use_feather,
                        int motion_blur_samples,
                        float motion_blur_shutter)
@@ -117,7 +121,10 @@ CachedMask::CachedMask(Context &context,
       for (const int64_t x : IndexRange(size.x)) {
         /* Compute the coordinates in the [0, 1] range and add 0.5 to evaluate the mask at the
          * center of pixels. */
-        const float2 coordinates = (float2(x, y) + 0.5f) / float2(size);
+        float2 coordinates = (float2(x, y) + 0.5f) / float2(size);
+        /* Do aspect ratio correction around the center 0.5 point. */
+        coordinates = (coordinates - float2(0.5)) * float2(1.0, aspect_ratio) + float2(0.5);
+
         float mask_value = 0.0f;
         for (MaskRasterHandle *handle : handles) {
           mask_value += BKE_maskrasterize_handle_sample(handle, coordinates);
@@ -175,11 +182,13 @@ void CachedMaskContainer::reset()
 CachedMask &CachedMaskContainer::get(Context &context,
                                      Mask *mask,
                                      int2 size,
+                                     float aspect_ratio,
                                      bool use_feather,
                                      int motion_blur_samples,
                                      float motion_blur_shutter)
 {
-  const CachedMaskKey key(size, use_feather, motion_blur_samples, motion_blur_shutter);
+  const CachedMaskKey key(
+      size, aspect_ratio, use_feather, motion_blur_samples, motion_blur_shutter);
 
   auto &cached_masks_for_id = map_.lookup_or_add_default(mask->id.name);
 
@@ -193,6 +202,7 @@ CachedMask &CachedMaskContainer::get(Context &context,
                                         mask,
                                         size,
                                         context.get_frame_number(),
+                                        aspect_ratio,
                                         use_feather,
                                         motion_blur_samples,
                                         motion_blur_shutter);
diff --git a/source/blender/nodes/composite/nodes/node_composite_mask.cc b/source/blender/nodes/composite/nodes/node_composite_mask.cc
index 8c9a4f10cf7..6f1a0375900 100644
--- a/source/blender/nodes/composite/nodes/node_composite_mask.cc
+++ b/source/blender/nodes/composite/nodes/node_composite_mask.cc
@@ -97,6 +97,7 @@ class MaskOperation : public NodeOperation {
         context(),
         get_mask(),
         domain.size,
+        get_aspect_ratio(),
         get_use_feather(),
         get_motion_blur_samples(),
         get_motion_blur_shutter());
@@ -127,6 +128,15 @@ class MaskOperation : public NodeOperation {
     return int2(node_storage(bnode()).size_x, node_storage(bnode()).size_y);
   }
 
+  float get_aspect_ratio()
+  {
+    if (get_flags() & (CMP_NODE_MASK_FLAG_SIZE_FIXED | CMP_NODE_MASK_FLAG_SIZE_FIXED_SCENE)) {
+      return 1.0f;
+    }
+
+    return context().get_render_data().yasp / context().get_render_data().xasp;
+  }
+
   bool get_use_feather()
   {
     return !bool(get_flags() & CMP_NODE_MASK_FLAG_NO_FEATHER);