Objective: To analyze and identify changes in the maxillary dental arch before and after cheiloplasty in a group of unilateral complete cleft lip and palate (UCLP) infants. Design: This is a cohort study. Material and Method: Study models from 16 infants with nonsyndromic UCLP, who were treated at Khon Kaen University, were taken before (T1) and after cheiloplasty (T2). The dental models underwent a process of scanning through a 3D scanner, from which 9 linear and 2 angular landmarks were evaluated. Paired t test was used to compare the measurement statistically between T1 and T2. Results: Alveolar cleft gap (G-L), anterior basal angle (∠GC-CC′), and anterior arch curvature angle on greater segment (∠GIC) were significantly decreased ( P < .05). Contrarily, anterior ridge length of greater segment (C-I), anterior ridge length of lesser segment (L-C′), and posterior arch width (T-T′) were significantly increased ( P < .05) after cheiloplasty. While, anterior portion of greater segment (I-G), anterior arch width (C-C′), anterior arch depth (I⊥CC′), arch length (G⊥TT′), and arch circumference (T-C-I-G-L-C′-T′) showed no significant difference. The measurements were tested using the Intraclass correlation coefficient. The coefficients indicated high reliability. Conclusion: Cleft gap significantly decreased after lip repair, and the anterior part of maxillary dental arch was also bent palatally after cheiloplasty without any other intervention except cheiloplasty. More studies are needed to assess the amount of lip pressure. If any convincing force is presented, an appliance to prevent undesirable pressure is indicated.