Purpose: To compare the social impact of malocclusion on quality of life between adult patients with Angle Class I, II and III malocclusion. Materials and Methods: A total of 222 adult patients (139, 42 and 41 with Angle Class I, II and III malocclusion, respectively) were recruited voluntarily from those attending the Orthodontic Clinic of Khyber College of Dentistry in Pesh awar, Pakistan. Participants were asked to complete the Urdu version of the short form of the Oral Health Impact Profile (OHIP-14), which was previously validated for this study. Multivariate analysis of variance (MANOVA) was used to compare the seven OHIP-14 domains scores and the total score between patients with malocclusion Class I, II and III. Results: Adults with Class III malocclusion had a significantly higher OHIP-14 total score than those with Class I malocclusion (a mean difference of 5 units between groups), but there were no differences between other Angle malocclusion groups. In addition, adults with Class III malocclusion reported greater impacts on the three OHIP-14 disability domains (physical, psychological and social) than those with Class I malocclusion. No significant interactions with sex and age were found. Conclusion: These findings suggest that adult patients with Class III malocclusion had a poorer quality of life than those with Class I malocclusion. Differences were mainly found in the physical, psychological and social disability domains of the OHIP-14 instrument. Keywords: adults, malocclusion, quality of life