Macrostomia is often associated with the first and second branchial arch syndrome. Depending on the involvement area, appearance may vary. In isolated cases of macrostomia, the cleft usually terminates at the medial border of the masseter muscle. The goal of macrostomia reconstruction is to achieve functional, symmetrical and accurate mouth commissure with minimal scar. In this article, we present an eight-year-old girl case with isolated bilateral macrostomia treated with vermillion-square flap method. We recommend this method for patients with mild to moderate macrostomia.