Episodic future thinking (EFT) refers to the mental simulation of future events that might be personally-experienced; a crucial mental process in adaptation. Psychiatric disorders are associated with deficits in recalling episodic memory, however, no study has reviewed the empirical literature to assess for similar deficits in EFT. A systematic review comparing psychiatric groups with control groups on the specificity and episodic detail of EFT returned 19 eligible studies. An overall effect of g = -0.84 (95%CI = -1.06, - 0.62, p < .001) indicated individuals with a psychiatric diagnosis have significantly less specific and detailed EFT. Publication bias was not detected, but heterogeneity was. No methodological characteristics were significant moderators. Subgroup analyses showed significant effects for depression (g = -0.79, p < .001, k = 7), bipolar disorder (g = -1.00, p < .001, k = 2), and schizophrenia (g = -1.06, p < .001, k = 6), but not posttraumatic stress disorder (g = -1.04, p = .260, k = 2) or complicated grief (g = -0.41, p = .08, k = 2). Deficits in EFT are apparent in some psychiatric disorders. However, many clinical groups are understudied, and the causal mechanisms and remediation of these deficits require further research attention.