OBJECTIVES: States vary significantly in their regulation of abortion. Misinformation about abortion is pervasive and propagated by state-mandated scripts that contain abortion myths. We sought to investigate women's knowledge of abortion laws in their state. Our secondary objective was to describe women's ability to discern myths about abortion from facts about abortion. STUDY DESIGN: This was a cross-sectional study of English- and Spanish-speaking women aged 18-49 in the United States. We enrolled members of the GfK KnowledgePanel, a probability-based, nationally-representative online sample. Our primary outcome was the proportion of correct answers to 12 questions about laws regulating abortion in a respondent's state. We asked five questions about common abortion myths. We used descriptive statistics to characterize performance on these measures and bivariate and multivariate modeling to identify risk factors for poor knowledge of state abortion laws. RESULTS: Of 2223 women contacted, 1057 (48%) completed the survey. The mean proportion of correct answers to 12 law questions was 18% (95% CI 17-20%). For three of five assessed myths, women endorsed myths about abortion over facts. Those who believe abortion should be illegal (aOR 2.18, CI 1.40-3.37), and those living in states with neutral or hostile state policies toward abortion (neutral aOR 1.99, CI 1.34-2.97; hostile aOR 1.6, CI 1.07-2.36) were at increased odds of poor law knowledge. CONCLUSIONS: Women had low levels of knowledge about state abortion laws and commonly endorse abortion myths. Women's knowledge of their state's abortion laws was associated with personal views about abortion and their state policy environment. IMPLICATIONS: Supporters of reproductive rights can use these results to show policy makers that their constituents are unlikely to know about laws being passed that may profoundly affect them. These findings underscore the potential benefit in correcting widely-held, medically-inaccurate beliefs about abortion so opinions about laws can be based on fact.