Abstract Families experience various kinds of problems and problems in caring for familymembers whose families experience various obstacles in treating a patient with mental disor-ders. One condition that is felt is anxiety. Anxiety is related to ignorance regarding the patient’scondition; earn a living; demands to divide time. The role of the family becomes very impor-tant because the patient lives in the middle of the family. Families need knowledge in managingpatients both when treated at the hospital and when returning home. The purpose of this studywas to determine the effect of family psychoeducation (FPE) therapy on family anxiety in treat-ing a patient with mental disorders. The design used a quasi-experiment with the pre-test andpost-test with control group methods. The sample was 100 respondents (50 experimental groupsand 50 control groups). The results of the study showed a significant effect of FPE on familyanxiety with a p-value of 0.00 (p < 0.05). It was concluded that FPE therapy effectively reducedfamily anxiety in treating a patient with mental disorders.© 2021 Elsevier Espa˜na, S.L.U. All rights reserved.