Purpose This study aims to determine the effect of psychoeducation, given to nurses working in a psychiatry clinic, on level of knowledge, attitudes, and practices regarding physical restraint. Design and Methods This study was conducted with a randomized-controlled-study design. A total of 111 nurses were recruited and randomly assigned to experimental (n = 53) and control (n = 58) groups. The experimental group received psychoeducation, while no intervention was applied to the control group. This study was conducted in a psychiatric hospital located in the Eastern Anatolia of Turkey. A Descriptive Form and the Levels of Knowledge, Attitudes, and Practices of Nurses Regarding Physical Restraints Questionnaire were used to collect data. Findings Statistically significant differences were found between the pretest and posttest total mean scores on the level of knowledge (P = .000), attitudes (P = .000), and practices (P = .000) of the nurses in the control group and the study group. Practice Implications An increase in the level of knowledge and positive improvement in attitudes and practices were observed in the nurses who received psychoeducation. Providing nurses with psychoeducation on physical restraint can positively contribute to improving their level of knowledge and to eliminating their negative attitudes and practices on this subject.