Context Human–animal interaction (HAI) is widely used as a method of reducing psychological distress. However, research findings in support of HAI have not kept pace with the widespread prevalence in practice. Objective I review and synthesize the quantitative evidence for the influence of HAI on psychological distress and outline future directions for research. Results The evidence suggests that HAI has a small‐to‐medium effect on distress but does not clarify whether animals account for the treatment effects. Research also has not determined whether positive effects observed in circumscribed HAI programs extend to companion animal ownership. Conclusion HAI research needs to address methodological limitations and expand the focus beyond treatment outcome studies. By increasing our understanding of the processes through which HAI reduces distress, the circumstances under which it is most effective at doing so, and the influence HAI has on the animals, we can enhance the impact of HAI.