To assess the regulations on Cannabis advertising across U.S. states for variation and compare with Canadian federal policies, for the purpose of identifying opportunities to protect the public, especially the youth and other vulnerable populations, from health risks. We reviewed Health Canada's and to identify prohibited marketing and advertising activities for cannabis products. The Canadian guidelines (where cannabis is legal for both medical and nonmedical use) were compared with regulations in the 36 U.S. states where cannabis is legalized for medical and/or adult (e.g., recreational) use. Cannabis advertising regulations vary greatly and have little consistency across the U.S. states. Most states do not address many of the cannabis advertising activities that are prohibited in Canada. Among the 31 states that do allow some form of cannabis advertising, 74% explicitly prohibit targeting or appealing to minors and 68% prohibit making false or misleading claims. There are 11 illegal advertising tactics in Canada, such as glamorization and testimonials, that were not specifically discussed in any of the U.S. state policies. The lack of consistent marketing guidelines could expose youth and vulnerable populations to cannabis advertisements; more widespread or federal guidance is needed.