Although there are studies on voting similarity in mate selection, very little research has examined party identification and relationship quality. We assessed associations between reports of personal and partner voting behavior (Democrat, Republican, or Independent) and both relationship adjustment and commitment to one's partner. We used a national (U.S.) sample of individuals (N = 510) in their 20s and 30s who were mostly in different-sex, serious relationships (Mdn duration = 5.25 years; 50% married). Controlling for age, college graduation, income, religiosity, minority status, and duration of relationship, voting Republican was associated with higher levels of commitment compared to voting Democrat. Similarly, being partnered with someone voting Republican was associated with higher relationship adjustment and commitment compared to being partnered with someone voting Democrat. Notably, differences in commitment were found only among those who were not already married or engaged. Findings were largely consistent with numerous online reports of survey data that have shown modestly greater relationship quality among those who report being politically conservative. While research has shown that people are less attracted to those who vote differently and that voting differently can be associated with lower relationship quality, we did not generally find perceived voting similarity to be associated with relationship adjustment or commitment. There was one exception: In exploratory analyses, Republicans paired with Democrats tended to report substantially lower relationship adjustment than if paired with Republicans. Implications for political differences among intimate partners and clinical work around these themes are discussed.