Expectations can influence the outcome and the process of psychotherapy. Hence, this article aims to overview the types of expectations, i.e., outcome, treatment and change. Both patients' and therapists' expectations are considered. Furthermore, determinants of expectations and moderators/mediators of expectations-outcome relationship are described. We provided theories that try to explain the influence of expectations and their relationship with the psychotherapy process. Various instruments for measuring expectations and practical advice to manage expectations in psychotherapy will be discussed. Clinicians should become increasingly aware of their own and clients' expectations. Future studies should investigate the impact of every kind of expectation and its moderation/mediation role with other psychotherapy processes.