diff --git a/Libraries/LibJS/Runtime/TypedArrayPrototype.cpp b/Libraries/LibJS/Runtime/TypedArrayPrototype.cpp
index 550351fcebc..471c2b98085 100644
--- a/Libraries/LibJS/Runtime/TypedArrayPrototype.cpp
+++ b/Libraries/LibJS/Runtime/TypedArrayPrototype.cpp
@@ -383,6 +383,25 @@ JS_DEFINE_NATIVE_FUNCTION(TypedArrayPrototype::copy_within)
             direction = 1;
         }
 
+        // OPTIMIZATION: Fast path for non-shared ArrayBuffers that are not detached and have enough space to perform the copy with memmove.
+        if (!buffer->is_shared_array_buffer()) {
+            Checked<size_t> from_end = from_byte_index;
+            from_end += count_bytes;
+            Checked<size_t> to_end = to_byte_index;
+            to_end += count_bytes;
+
+            if (!from_end.has_overflow()
+                && !to_end.has_overflow()
+                && from_end.value() <= buffer_byte_limit
+                && to_end.value() <= buffer_byte_limit) {
+                auto* base = buffer->buffer().data();
+                void const* src = base + from_byte_index;
+                void* dst = base + to_byte_index;
+                memmove(dst, src, count_bytes);
+                return typed_array;
+            }
+        }
+
         // n. Repeat, while countBytes > 0,
         while (count_bytes > 0) {
             // i. If fromByteIndex < bufferByteLimit and toByteIndex < bufferByteLimit, then