Purpose: Many studies have investigated the impact of prosthetic treatment on oral health-related quality of life (OHRQoL). However, most of these have been performed among fully or partially edentulous patients. Studies involving patients with a single missing tooth are limited. The purpose of this study was to compare the OHRQoL between patients treated by single-tooth implants and three-unit fixed partial dentures (FPDs) for single missing tooth restoration. Materials and Methods: A cross-sectional survey was conducted in Korea with patients drawn by stratified purposive sampling based on age. OHRQoL was measured using the Korean version of the 14-item Oral Health Impact Profile (OHIP-14K) questionnaire. Pre- and posttreatment OHIP-14K scores were compared by paired t test. Single-tooth implants and three-unit FPDs were compared by two-sample t test. In addition, multiple regression analysis was used to evaluate the impact of treatment mode on OHIP-14K total score after adjusting the effect of demographics and clinical factors. Results: Thirty-five patients with single-tooth implants and 36 patients with three-unit FPDs were included. All participants had a significant improvement in OHRQoL compared with before the treatment (P .0001). However, there was no statistically significant difference in the change of OHIP-14K score between the two treatment modes. In addition, the treatment mode had no significant impact on the change of OHIP-14K total score after adjusting the influence of covariates (P = .170). Conclusion: Both single-tooth implants and three-unit FPDs for single missing tooth replacement resulted in significant and similar improvement of OHRQoL. Keywords: OHIP-14, oral health impact profile, oral health-related quality of life, single missing tooth, single-tooth implant, three-unit fixed partial denture