BackgroundCannabis marketing exposure via social media may impact use in youth and young adults. Most states with recreational cannabis lack policies regarding social media-based marketing. Thus, we examined such policies among prominent platforms, particularly those popular among youth and young adults.MethodsIn September-October 2022, 3 research team members extracted policies applying to the general community, advertising, and any specific content regarding drug-related content for 11 social media sites: Discord, Facebook, Instagram, Pinterest, Reddit, Snapchat, TikTok, Tumblr, Twitch, Twitter, and YouTube. Using inductive thematic analysis, they then dual-coded restrictions on cannabis-related content (e.g., paid advertising, unpaid promotion, sales). Descriptive analyses were conducted.ResultsTen (all except TikTok) referenced cannabis/marijuana, 7 (all except Discord, Instagram, TikTok, and YouTube) distinguished different cannabis-derived products, and 5 (Reddit, Snapchat, TikTok, Tumblr, Twitter) noted jurisdictional differences in cannabis regulations/legality. All prohibited sales, 9 (all except Snapchat and Tumblr) prohibited paid advertising, and 4 (Discord, Reddit, Snapchat, TikTok) prohibited unpaid promotion (e.g., user-generated content). All restricted underage access to cannabis-related content. However, policies varied and were ambiguous regarding how “promotion” was defined, whether/how jurisdictional differences in legality were addressed, how businesses may interact on social media, barriers implemented to inhibit the facilitation of sales, and enforcement protocols.ConclusionsSocial media policies regarding cannabis marketing are ambiguous and may facilitate cannabis marketing, promotion, sales, and underage exposure, thus compounding concerns regarding insufficient governmental regulations. Greater specificity in social media cannabis-related policies and enforcement is needed.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13011-023-00546-x.