Participants were HIV-negative GBM at an increased risk of HIV (more than five partners or condomless anal intercourse in the previous 3 months) enrolled in a randomised controlled trial of HIV self-testing. The baseline questionnaire captured data regarding sociodemographic characteristics, HIV and/or sexually transmissible infection testing history, sexual behaviour, beliefs and attitudes towards HIV and eight items capturing confidence in HIV testing ability that were combined as a single broad measure of HIV testing self-efficacy (α=0.81). Factors associated with three or more HIV tests in the past year and the likelihood of self-testing in the future were determined using logistic regression. Of 354 GBM, 34% reported three or more HIV tests in the past year, and 64% reported being 'very likely' to self-test. Factors independently associated with three or more HIV tests in the past year were: higher self-efficacy (adjusted odds ratio (aOR) 1.08 per unit increase; 95% confidence interval (CI) 1.02-1.14; P=0.004); >10 male partners in the past 6 months (aOR 1.79; 95% CI 1.05-3.04; P=0.031) and higher optimism regarding the effects of HIV treatments on HIV transmission (aOR 1.14; 95% CI 1.00-1.29; P=0.044). Only higher self-efficacy was independently associated with reporting a greater likelihood to self-test in the future (aOR 1.10; 95% CI 1.05-1.15; P < 0.001). Improving self-efficacy by enhancing GBM's knowledge and experience may lead to higher testing frequency. The self-efficacy measure used in the present study could be useful in identifying GBM likely to face difficulties with HIV testing and self-testing.