Although recent work has begun to establish that early modern plagues had selective mortality effects, it was generally accepted that the initial outbreak of Black Death in 1347‐52 was a “universal killer.” Recent bioarchaeological work, however, has argued that the Black Death was also selective with regard to age and pre‐plague health status. The issue of the Black Death's potential sex selectivity is less clear. Bioarchaeological research hypothesizes that sex‐selection in mortality was possible during the initial Black Death outbreak, and we present evidence from historical sources to test this notion. Objective To determine whether the Black Death and recurring plagues in the period 1349–1450 had a sex‐selective mortality effect. Materials and Methods We present a newly compiled database of mortality information taken from mortmain records in Hainaut, Belgium, in the period 1349–1450, which not only is an important new source of information on medieval mortality, but also allows for sex‐disaggregation. Results We find that the Black Death period of 1349–51, as well as recurring plagues in the 100 years up to 1450, often had a sex‐selective effect—killing more women than in “non‐plague years.” Discussion Although much research tends to suggest that men are more susceptible to a variety of diseases caused by bacteria, viruses and parasites, we cannot assume that the same direction of sex‐selection in mortality applied to diseases in the distant past such as Second Pandemic plagues. While the exact reasons for the sex‐selective effect of late‐medieval plague are unclear in the absence of further data, we suggest that simple inequities between the sexes in exposure to the disease may not have been a key driver.