BACKGROUND: Legislative and judicial procedures related to banning abortion after 6 weeks of gestation in Ohio occurred from November 2018 to July 2019. These activities could have increased the belief that abortion has become illegal even though the 6-week abortion ban has never been in effect to date. OBJECTIVE: We sought to determine the prevalence and correlates of holding the belief that abortion is illegal in Ohio and to evaluate whether this belief increased over the time in which the 6-week abortion ban was introduced, passed twice, and then blocked in Ohio. STUDY DESIGN: We analyzed data from the first wave of the Ohio Survey of Women, a population-based survey of adult, reproductive-aged Ohioan women conducted from October 2018 to June 2019. During each of the 8 survey months, a median of 240 women (range, 70e761) completed the survey, including the survey question "Based on what you know or have heard, is it legal to get an abortion in your state?" We used multivariable logistic regression to assess the prevalence and correlates of believing that abortion is illegal in the state of Ohio. In addition, we used multinomial logistic regression to evaluate whether this belief increased over the interval during which women completed the survey, which roughly corresponded to the interval marked by legislative and judicial activities surrounding the 6-week abortion ban. RESULTS: Most of the 2359 participants understood that abortion is legal in the state of Ohio (64.0%) with the remainder believing it to be illegal (9.8%) or being unsure (26.2%). Correlates of believing abortion to be illegal included younger age, lower socioeconomic status, never married or married status, and black, non-Hispanic race and ethnicity. Being unsure about legality did not change over time; however, the proportion of women who believed that abortion is illegal increased from the first month (4.5%) to the last month (15.9%) of the study period. Each additional study month was associated with a 17% increase in the odds of believing abortion to be illegal, in both unadjusted and adjusted models (odds ratio, 1.17; 95% confidence interval, 1.08e1.27). CONCLUSION: Attempts to restrict abortion access could contribute to women mistakenly believing that abortion is illegal despite it being unsuccessful.