Objective <p>To examine the association between the frequency of cannabis use and adherence to COVID-19 public health guidelines among adults in France between April and October 2020.</p> Methods <p>Data from the CONSTANCES cohort on 39,450 adults participating in the SAPRIS survey were analyzed. The associations between non-adherence to handwashing, mask-wearing and social distancing and cannabis use frequency in 2019 at two periods of time, wave 1 + 2 (confinement) and wave 3 (deconfinement), were examined using binary logistic regression. The models were adjusted for age, sex, education, marital status, accommodation, tobacco use, self-rated health, anxiety and depressive symptoms.</p> Results <p>Compared to no cannabis use during the past 12 months, cannabis use less than once per month was negatively associated with handwashing at wave 3 (Odds Ratio [95% Confidence Interval]) 1.46 [1.28–1.66], mask-wearing at wave 1 + 2 (1.26 [1.05–1.52]) and at wave 3 (1.60 [1.35–1.89]) and social distancing at wave 1 + 2 (1.32 [1.16–1.50]) and at wave 3 (1.55[1.32–1.83]). Cannabis use once per month or more was negatively associated with mask-wearing at wave 3 (1.41 [1.11–1.80]) and social distancing at wave 1 + 2 (1.27 [1.06–1.52]) and at wave 3 (1.57 [1.25–1.98]).</p> Conclusion <p>Cannabis use may be associated with less adherence to COVID-19 public health guidelines.</p>