Objectives: To examine physical activity (PA) levels, and how sociocultural factors, acculturation, self-efficacy and religion influence PA levels of Arab Muslim mothers of young children living in the United States.Design: Cross-sectional online survey.Participants and Setting: Arab Muslim mothers of young children (aged <5 years) living in the United States (N=447).Variables Measured: PA levels, sociocultural and religious barriers to PA, self-efficacy, strength of religious faith, and acculturation.Results: Barriers to PA included dress code and negative perception of women who engaged in PA, lack of motivation and stress, and responsibilities. Barriers and self-efficacy significantly influenced PA levels (P<.001) but strength of religious faith and acculturation did not.Conclusions: Confirmation of the relations among self-efficacy, barriers and PA levels among Arab Muslim mothers of young children in the United States may help professionals tailor culturally sensitive interventions to combat obesity and other chronic diseases among this growing population.Ethn Dis. 2019;29(3):469-476; doi:10.18865/ ed.29.3.469