From 2000 through 2008, initiatives proposing to ban same-sex marriage were on the ballot in 28 states. Although same-sex marriage opponents scored lopsided victories in most cases, voting outcomes varied substantially at the county level. This article examines sources of that variation and argues that opposition to same-sex marriage should be strong in communities characterized by the predominance of traditional gender roles and family structure. Perhaps more interestingly, the analysis also shows that the effects of traditional family structure and gender roles are especially strong in counties characterized by weak community cohesion, as indicated by residential instability, low rates of home ownership, and high crime rates. (Contains 12 footnotes, 7 tables, and 2 figures.)