We performed a systematic review to estimate the proportion of men who have sex with men (MSM) in Asia who are bisexual and compare prevalence of HIV and sexual risk between men who have sex with men and women (MSMW) and men who have sex with men only (MSMO). Forty-eight articles based on 55 unique samples were identified from nine countries in Asia. Bisexual behaviour was common among MSM (pooled prevalence 32.8 %). Prevalence of HIV (pooled OR 0.90; 95 % CI 0.77-1.05), recent syphilis infection (pooled OR 0.99; 95 % CI 0.93-1.06) and unprotected anal intercourse (pooled OR 0.80; 95 % CI 0.57-1.11) were similar between MSMW and MSMO, but heterogeneity was high. MSMW had lower odds of reporting a prior HIV test than MSMO (OR 0.82; 95 % CI 0.70-0.95; p = 0.01, I2 = 0 %). Targeted interventions are needed to increase uptake of HIV testing among MSMW. Increased reporting of disaggregated data in surveillance and research will help improve understanding of risk in MSMW and inform targeted interventions.