Previous research has found that people who experience homelessness are more likely to also experience gambling problems. The authors did a systematic review to understand how common problem gambling and gambling disorder are among people experiencing homelessness. They searched the databases Medline, Embase, and PsychINFO for studies that met the inclusion criteria. Eight articles from five countries were included in the review. The eight studies reported information on 1938 participants. Rates of problem gambling and gambling disorder ranged from 11.3% to 31.3%. High rates of subclinical problem gambling were reported (11.6–54.4%). The review shows that at least one in ten people experiencing homelessness also experiences problem gambling or gambling disorder.