Abstract Orthodontists can choose between several types of preformed archwires that can alter the patient's arch form. Since arch form appears to be a determinant of smile esthetics, the intent of this study is to compare arch form parameters in consonant and nonconsonant smiles. The frontal posed smile photographs and study models of 30 females with consonant smile and 30 females with nonconsonant smile were obtained from the students of dentistry in the University of Rafsanjan (age between 20 and 25). Intermolar width (IMW) and intercanine width; molar arch depth (MAD) and canine arch depth (CAD); ratio of sum of 6 anterior tooth material (SUM) to canine arch depth (CAD) and that's ratio to intercanine width (ICW); distance between the incisal edges of the central incisors (CI) and lateral incisors (LI) and cusp tips of canines (CT) to the tangent line to the superior border of lower lip curvature (LLC) during smile were measured and compared between two groups. Result Only the distance between the incisal edges of the central incisors and lateral incisors to the curvature of lower lip during smile show significant differences between two groups.