As a worldwide social movement, skepticism aims to promote science and critical thinking. However, by analyzing texts published in the magazine of the Finnish skepticism movement between 1988 and 2017, we find that the movement carries out its mission in a way that maintains and produces gendered hierarchies. We identify six forms of gendered boundary-work in the data: science as masculine, questioning women, complementary and alternative medicine as feminine, debating the status of gender studies, gender within the skepticism movement, and (...) supporting equality. Gender is an important aspect of the boundary-work undertaken by the movement to establish boundaries between science and nonscience. The forms of gendered boundary-work contribute to the idea of “true” science as a masculine and male-dominated domain, excluding women from both science and the skepticism movement. Even when the exclusions are subtle, hidden, or humorous, they nevertheless produce gendered inequalities by excluding women, belittling women’s knowledge production, or granting women-only dismissive recognition. Indeed, our analysis indicates that there is a need to look deeply into science-based social movements: exclusive structural tactics are part and parcel of such movements’ mundane activities, as our examples from Skepsis ry’s popular magazine demonstrate. (shrink)