Dramatic shifts in marijuana laws, along with federal deregulation of hemp with the 2018 Farm Bill, have resulted in increased availability and use of cannabidiol (CBD) supplements throughout the United States (US). Given the rapid increase in CBD use in the U.S. general population, in this study, we aim to characterize primary care physician (PCP) attitudes and practice behaviors and to assess whether differences in provider attitudes and behaviors vary as a function of marijuana legalization (ML) status in the state of practice. Data are from an online provider survey on CBD supplement-related attitudes, beliefs, and behaviors administered to 508 PCPs as part of a larger mixed methods study. Participating PCPs were recruited from the Mayo Clinic Healthcare Network and provided medical care in primary care settings across four U.S. states (Minnesota, Wisconsin, Florida, and Arizona). The survey response rate was 45.4% (=236/508). According to providers, CBD was frequently brought up in PCP settings, typically by patients. PCPs were generally hesitant to screen for or discuss CBD with their patients and identified multiple barriers to open patient-provider dialogue about CBD. PCPs practicing in states that had passed ML were more receptive to patients using CBD supplements, whereas PCPs practicing in states that had not passed ML were more concerned about CBD-related side effects. Regardless of state ML status, most PCPs did not feel that they should be recommending CBD supplements to their patients. Most PCPs reported believing that CBD was unhelpful for most conditions for which it is marketed, with chronic non-cancer pain and anxiety/stress being exceptions. PCP respondents generally felt that they had insufficient knowledge/training around CBD. Results from this mixed methods study show that PCPs practicing in the U.S. rarely screen for or discuss CBD use with their patients and report several barriers to engage in proactive CBD-focused practice behaviors. Furthermore, survey results show that some PCP attitudes, practice behaviors, and barriers vary as a function of state ML status. These findings may guide medical education efforts and inform primary care practice modifications aimed at enhancing screening and monitoring of patient CBD use by PCPs.