Objectives Gender norms, especially among men, can reduce the effectiveness of HIV prevention programs. We sought to assess the association between attitudes towards gender norms and risky sexual behaviours, and identify sociodemographic factors that predict gender-inequitable and masculinity norms among men in western Jamaica. Methods: A cross-sectional, survey of 549 men aged 19-54 years was conducted. Attitudes towards gender norms were measured using the Gender Equitable Men and Macho scales. Logistic regression and general linear models were used to assess associations between gender norms and multiple sexual partners, and to identify the associated sociodemographic factors. Adjusted odds ratios (AORs) and 95% confidence intervals (CIs) are presented. Results: Fifty-four percent of the participants (mean age≤32.4 years) reported multiple sex partners and 22% reported unprotected sex with non-regular partner in the past 12 months. Men with moderate (AOR≤2.2; 95% CI≤1.4-3.3) and high (AOR≤4.2; 95% CI≤2.0-8.5) support for inequitable gender norms, and moderate (AOR≤1.7; 95% CI≤1.1-2.7) and high (AOR≤2.5; 95% CI≤1.5-4.3) support for masculinity norms were more likely to report multiple sex partners. Similarly, men with moderate (AOR≤2.4; 95% CI≤1.3-4.3) and high (AOR≤2.5; 95% CI≤1.2-5.2) support for inequitable gender norms were more likely to report unprotected sex with a nonregular partner. Conclusion: A high proportion of Jamaican men engage in risky sexual behaviours. These results highlight the need for behaviour change interventions addressing gender norms targeting Jamaican men. © CSIRO 2014.