This article argues that the Eugenics Society sought the best possible relations with the labour movement between its founding in 1907 and 1945. It examines how the Society regarded socialism, Labour, and workers. At the local and individual levels, relations were often very good. Starting in 1910 with some lectures to the Fabians and other socialist groups, by the mid-1930s the working class had become the Society's principal audience. It was wedded to party-political neutrality. However, in order to shed its bourgeois reputation, it promoted Labour supporters within the Society. There is evidence for this from 1928 onwards. It also tried to make eugenics appealing to socialists. In this way, it hoped to gain support for voluntary sterilization after 1931 from the Party which was the most sceptical about its benefits. More generally, it wished to overcome Labour hostility. Eugenics accordingly became more progressive. This is exemplified by the Society's emphasis in the 1930s of increasing the birth rate of healthy, upstanding, and intelligent people of whatever social class. Prior to that, it had been obsessed with differential fertility, and had regarded economic status as an indicator of social worth.