This study investigates how a lack of social support differentially affects men and women’s colorectal cancer (CRC) screening participation, considering different screening strategies implemented across European countries. Although health sociology has stressed gender differences in social support and its effects on health behaviours, this was overlooked by cancer screening research. Using a data set of 65,961 women and 55,602 men in 31 European countries, we analysed the effect of social support variables on CRC screening uptake. We found that living alone and lower perceived social support were associated with lower screening uptake for both men and women. These effects were, however, stronger among men. Population‐based screening programmes mitigated these effects, particularly for women, but not for men living alone. In countries with opportunistic screening programmes, social support variables remained associated with screening uptake. We conclude that cancer screening interventions should pay attention to social support and its gender‐differentiated effects.