Please use this link to access this publication. Abstract Background While a key goal of liberalizing cannabis policy is to reduce harms related to criminal justice involvement, the degree to which this occurs and how it varies by policy format is uncertain. We completed a systematic review of changes in cannabis offences overall and across subgroups after cannabis policy liberalization. Methods A search of 7 databases was conducted for studies examining changes in cannabis offences, including arrests, charges, convictions, and referrals, before and after cannabis policy changes. Four types of cannabis policy change were considered: medical legalization, non-medical decriminalization, non-medical legalization, and non-medical commercialization....