A systematic review of the literature was performed to summarize cannabis use among adolescents and young adults during the COVID-19 pandemic. Special focus was given to the prevalence of cannabis use during COVID-19, as well as factors that may explain changes in cannabis consumption patterns. The protocol of this systematic review was registered. Articles from seven publication databases were searched in January 2022. The inclusion criteria for studies were as follows: 1) published in English; 2) study instruments needed to include items on COVID-19; 3) conducted after January 1st, 2020; 4) published in a peer-reviewed journal, dissertation, or thesis; 5) study population ≤25 years of age; 6) study designs were limited to observational analytical studies; 7) measured cannabis use. This review excluded other reviews, editorials, and conference abstracts that were not available as full text manuscripts. Independent review, risk of bias assessment, and data abstraction were performed by two authors. Fifteen articles from the United States (n=11) and Canada (n=4) were included in this review. The findings of this review showed that the prevalence of cannabis use during the pandemic among adolescents and young adults were mixed. Some mental health symptoms, including depression and anxiety, were identified as the most commonly reported reasons for increased cannabis use during the pandemic. This review highlights the inconsistencies in the prevalence of cannabis use among adolescents and young adults during the pandemic. Therapeutic interventions for mental health and continued public health surveillance should be conducted to understand the long-term effects of cannabis use among adolescents and young adults.