Conventional wisdom suggests that union members and their families are more politically active, and more likely to vote, than nonmembers. This study presents, to our knowledge, the first systematic empirical examination of that conventional wisdom. Results suggest that union members are more likely than nonmembers to vote in a general election, and that union campaign efforts increase voter turnout generally. There is no evidence, however, that union family members are more likely to vote than nonmembers, or that union status affects an individual’s likelihood of voting in a primary election.