We provide new evidence on how a gender-biased, labor-saving technology—the milking machine—advanced one important dimension of gender equality: women’s political representation. Our focus is mid-20th-century Finland, where mechanized milking reduced the time burden of a task traditionally performed by women and facilitated modernization of rural parts of the country. Using historical data, we estimate panel and instrumental-variable models that exploit temporal variation in the spread of milking machines and geographic variation in pre-determined comparative advantage in cattle farming. We find that municipalities with greater adoption of milking machines experienced significantly larger increases in the share of local council seats held by women between 1930 and 1972. These effects operated through time savings for women on dairy farms and rural economic development, against a backdrop of rising female off-farm employment, which together likely helped ease key constraints to women’s political representation.