We study how considerations of male circumcision (MC) as both a favourable practice and as protective against HIV are linked with ethnicity in sub-Saharan Africa, where many ethnic groups do not traditionally circumcise. We focus on Malawi, a country with a high HIV prevalence but low MC prevalence. Survey data from a population-based random sample in rural Malawi (N =3400) were analysed for ethnoregional patterns in attitudes towards MC. We used logit regression models to measure how reported circumcision status, region of residence and ethnic identity relate to attitudes towards circumcision. Overall, Malawians reported more negative than positive opinions about MC, but attitudes towards circumcision varied by ethnicity and region. The implications for agencies and governments aggressively scaling up the provision of MC are clear; acceptance of circumcision as a tool for HIV prevention could be low in societies divided by ethnoregional identities that also shape the practice of circumcision.