AimTo examine the effect of training provided to type 2 diabetes patients according to the theory of planned behavior on self-efficacy and patient empowerment. MethodsThis study, pre-test-post-test active control group single-blind experimental design, was conducted in the internal medicine outpatient clinic of a state hospital between April and October 2023. Participants were randomly assigned to the intervention group (IG; n=45) and control group (CG; n=47). The intervention group received a theory-based training program consisting of 5 sessions lasting approximately 40minutes each. Diabetes Management Self-Efficacy Scale, Patient Empowerment Scale and the patient's laboratory results were used for data collection. ResultsIn the study, while the posttest self-efficacy and patient empowerment scores of the intervention group increased compared to the pretest, there was an decrease in HbA1C level. On the post-test measurements between groups, self-efficacy and patient empowerment scores were higher and effect sizes were higher in the intervention group, while no difference was found in HbA1C values. ConclusionThe training program provided according to the theory of planned behavior in diabetes patients provides positive contributions to disease management.