Research on the economic activity of immigrant women has flourished in recent years. The current study extends this literature to examine the labor force activity of Arab-American women, a group whose labor market experiences provide an exception to hitherto accepted theoretical explanations. The employment rates of Arab immigrant women rank among the lowest of any immigrant group, while the rates of native-born Arab-American women resemble those of U.S.-born white women. This study examines potential explanations for these differences using data from the U.S. Census and a national mail survey of Arab-American women. Contrary to findings for other immigrant groups, differences among Arab-American women cannot be explained by their human capital characteristics or family resources, but are almost entirely due to traditional cultural norms that prioritize women's family obligations over their economic activity, and to ethnic and religious social networks that encourage the maintenance of traditional gender roles. This study concludes by underscoring the need for additional research on the impact of culture on immigrant women's employment.