Introduction: Many health care providers would benefit from greater knowledge and awareness of medical cannabis, even if they choose not to integrate it into their medical practice. Unfortunately, health care providers generally report low knowledge of medical cannabis and cite this lack of knowledge as a barrier to making patient recommendations. It is important to understand health care providers' medical cannabis knowledge and its correlates. However, few studies have rigorously assessed clinically relevant cannabis-related knowledge, instead typically focusing on attitudes toward cannabis and perceived knowledge. Methods: Physicians in a university-affiliated health system completed an anonymous online survey. The survey assessed participants' basic demographics and medical experience, experiences with cannabis education, beliefs about their knowledge of and competency regarding medical cannabis, and knowledge of medical cannabis in relation to the current scientific evidence. Results: The average level of medical cannabis knowledge was 58% correct, with scores ranging from 39% to 78% correct. Perceived cannabis knowledge predicted actual knowledge, and those who pursued self-initiated study or attended a lecture on medical cannabis had higher knowledge levels. Conclusion: Levels of factual knowledge about medical cannabis among physicians were moderate. Our results highlight the mismatch between physician knowledge and cannabis policy. We offer our brief, 10-min assessment as a baseline for characterizing cannabis knowledge, acknowledging that the content and interpretation may change as knowledge advances.