This study examines the economic mobility of single mothers. It highlights the relationships between single mothers' financial assets and human capital development (educational advancement, job training, and work hours) with their economic mobility. Analysis of data from the National Longitudinal Survey of Youth (NLSY79) indicates that assets may help improve upward economic mobility. Assets, however, have differential impact on single mothers with different income levels. In addition, human capital development mediates the positive link between assets and the economic mobility for mothers living between the 100% and 200% federal poverty. These results support asset building as an investment strategy to enhance the long-term economic wellbeing of single mothers. The findings also underscore the importance of examining within-group variations among single mothers in designing effective asset-building policies and programs.