In the Roman imperial worldview, masculine, civilized Rome saw a duty to control and care for uncivilized, feminine foreigners—a gendered power dynamic shared by more recent colonizing states as well. However, it is a methodological challenge to catch sight of the way such a worldview may have impacted colonial subjects. I examine the impact in Roman Britain and Gaul by applying a symbolic anthropological approach to a well-suited body of evidence, votive offerings: widely accessible and highly individual, each represents a single symbolic act. Taking up archaeological questions of material symbolism, I analyse the confluence of gender and offering material categories. Analysis of objects men and women offered at 10 sanctuaries in Britain and Gaul, and of the materials in which men and women were portrayed, reveals a permeability–impermeability binary: women are associated with breakable clay, porous bone and translucent glass, and men with strong, durable metal. This binary reflects Roman understandings of femininity and masculinity, shedding light on the fraught relationship between colonial rule and gendered understandings of the world.