The 420 Collaboration is an annual campaign to "create and improve cannabis-related content at Wikipedia and other Wikimedia projects in a variety of fields", including culture, health, hemp, history, medicine, politics and religion. Campaigns were held in 2017, 2018, 2019, 2020, and 2021. The 2022 campaign ran during March and April, and was organized around curated lists of redlinks or at-will article creation and improvement on English Wikipedia (or media contributions to Wikimedia Commons).