OBJECTIVE To identify risk factors associated with surgical site infection (SSI) in dogs following tibial plateau leveling osteotomy (TPLO). DESIGN Retrospective cohort study. ANIMALS 320 dogs that underwent unilateral or bilateral TPLO (n = 405 procedures) between 2007 and 2015 and were reexamined by a veterinarian at least once ≥ 8 weeks after the procedure. PROCEDURES Data were extracted from medical records regarding signalment, TPLO procedure details, medical history of dermatitis, and SSI status. Logistic regression was performed to identify factors associated with SSI development. RESULTS An SSI developed following 34 (8.4%; 95% confidence interval [CI], 6.1% to 11.5%) procedures. Prophylactic antimicrobial administration was provided following 36.8% (n = 149) of procedures. For 71 (17.5%) procedures, the dog had dermatitis at the time of surgery; 12 of these procedures involved dermatitis at the surgical site. The incidence of SSI following the 12 procedures for dogs with dermatitis at the surgical site was 16.7% (2/12 [95% CI, 3.3% to 54.3%]) and was 10.2% (6/59 [95% CI, 4.5% to 21.3%]) for dogs with dermatitis elsewhere; however, these differences in incidence were not significant. On multivariable analysis, German Shepherd Dogs (vs other breeds), meniscectomy (vs no meniscectomy), and attending surgeon having performed ≤ 20 (vs > 20) procedures during the study period were associated with increased odds of SSI. CONCLUSIONS AND CLINICAL RELEVANCE SSI following TPLO was associated with the German Shepherd breed, meniscectomy, and surgeon. Prospective studies are needed to investigate the mechanisms underlying these associations.