Nearly 40 million workers are employed in retail and service occupations. While the average age and educational attainment of workers in these occupations has increased significantly since the 1970s, many of these occupations offer low wages, along with limited fringe benefits and opportunities for advancement. These occupations also employ a disproportionate share of Black and Hispanic women. Using longitudinal data from the 2004 and 2008 Survey of Income and Program Participation which provide occupational data over a four year timespan, we evaluate the prevalence of occupational mobility by sex, race, and ethnicity. This research shows there are racial disparities in occupational mobility, with Black and Hispanic women less likely to exit retail and service occupations than White, non-Hispanic women. Educational attainment increased the likelihood of occupational mobility. Hispanic women’s lower levels of educational attainment depressed their occupational mobility, while longer job tenure increased the likelihood they would be occupationally mobile. Differences in human capital and job tenure did not explain mobility disparities between Black and White, non-Hispanic women. However, unionization reduced occupational mobility and partly accounts for Black women’s lower rates of mobility. Black women were more likely to be unionized and unionization was associated with decreased occupational mobility among women. Workers in unionized retail and service occupations earned higher wages, reducing the incentive to leave and lowering their occupational mobility rate.