Many aggregate-level studies suggest a relationship between economic inequality and sociodemographic outcomes such as family formation, health, and mortality; individual-level evidence, however, is lacking. Nor is there satisfactory evidence on the mechanisms by which inequality may have an effect. We study the determinants of transitions to a nonmarital first birth as a single parent or as a cohabiting parent compared to transitions to marriage prior to a first birth among unmarried, childless young adults in the National Longitudinal Survey of Youth, 1997 cohort, from 1997 to 2011. We include measures of county-group-level household income inequality and the availability of jobs typically held by high school graduates that pay above-poverty wages (i.e., middle-skilled jobs). We find that greater income inequality is associated with a reduced likelihood of transitioning to marriage prior to a first birth for both women and men. The association between levels of inequality and transitions to marriage can be partially accounted for by the availability of middle-skilled jobs. Some models also suggest that greater income inequality is associated with a reduced likelihood of transitioning to a first birth while cohabiting.