Aim: To evaluate potential pharmacogenetic effects of UGT1A1 polymorphisms on the pharmacokinetics (PK) of dolutegravir (Tivicay^®; ViiV Healthcare, NC, USA), an HIV-1 integrase inhibitor. Patients & methods: Analysis of pooled data from nine Phase I and II clinical studies was undertaken for 89 subjects receiving repeat dolutegravir 50 mg once daily (tablet formulation) who were genotyped for known UGT1A1 functional variants. Results: Geometric mean ratio (92% CI) for subjects carrying low (*28/*28 and *28/*37) and reduced activity (*1/*6, *1/*28, *1/*37, *28/*36 and *36/*37) polymorphisms compared with subjects with normal activity (*1/*1 and *1/*36) showed decreased oral clearance (CL/F; 0.765 [92% CI: 0.659–0.889]), increased area under the concentration–time curve (AUC_0-τ; 1.307 [1.125–1.518]) and C_max (1.221 [1.063–1.402]), respectively. Conclusion: Increased dolutegravir exposure in carriers of UGT1A1 reduced function polymorphisms is not clinically significant based on accumulated safety data so dose adjustment in these individuals is not required.