Purpose This research is conducted to evaluate the effect of assertiveness training in schizophrenic patients on functional remission and assertiveness level. Design and methods The research is designed as a randomized controlled trial with a pretest and posttest control group and repeated measures. Assertiveness training was carried out for a total of 8 weeks with the experimental group. Findings Assertiveness training in schizophrenic patients was found to be effective in increasing the functional remission and assertiveness levels of patients. Practice implications Assertiveness training in schizophrenia should be implemented by psychiatric nurses within the scope of rehabilitation services.