[Excerpt] Women, including 25.1 million working mothers with children under age 18, are a major force in our economy. Over the years, many mothers have joined the labor force, and their role as economic providers for their families has increased. In 2015, 69.9 percent of mothers with children under age 18 were in the labor force, representing over a third (34.2 percent) of working women. Moreover, mother-only families made up nearly a quarter of families with children. While their role in the paid labor force has changed, mothers continue to carry a disproportionate share of the unpaid household and caregiving responsibilities. At the same time, they still face a lack of adequate workplace supports and encounter barriers that prevent them from achieving economic security for themselves and their families. This issue brief presents statistics and information on working mothers, highlighting their employment characteristics, the changing structure of families, the poverty status of working mothers and their families, mothers as sole or primary earners, and unpaid caregiving and household responsibilities. The final section of the issue brief highlights some policies and workplace supports for working parents and their families.