Although cannabis’ major psychoactive component, Δ-9-tetrahydrocannabinol (THC), has been linked to both earlier onset and poorer outcomes of psychotic disorders, Cannabidiol (CBD) seems to have different pharmacological mechanisms and potential therapeutic properties. However, no clinical study has investigated CBD for the treatment of co-occurring psychotic and cannabis use disorders so far, even though its utility seems grounded in a plausible biological basis. The aim of this work is thus to provide an overview of available clinical studies evaluating the efficacy of CBD for psychotic symptoms induced by THC, schizophrenia, and cannabis use disorders. After searching for relevant studies in PubMed, Cochrane Library, and ClinicalTrials.gov, we included 10 clinical studies. Available evidence suggests that CBD may attenuate both psychotic-like symptoms induced by THC in healthy volunteers and positive symptoms in individuals with schizophrenia. In addition, preliminary data on the efficacy of CBD for cannabis use disorders show mixed findings. Evidence from ongoing clinical studies will provide insight into the possible role of CBD for treating psychotic and cannabis use disorders.