This paper investigates the impact of school peers on an individual's adult romantic relationships. In particular, we consider the effect of quasi-random variation in the share of black students within an individual's cohort on the percentage of adult relationships that are with blacks. We find that the share of blacks in a given cohort has a positive impact on the share of relationships with blacks later in life. The results remain when we consider cohabiting couples, and also when we focus on a subsample of relationships that were formed in a different state from that where an individual attended school. This suggests that the racial mix of schools has an important impact on racial attitudes.