Background: There has been some research on the impact of acceptance and commitment therapy on job stress, occupational depression and perception, but there is a research gap on the impact of group counseling on acceptance and commitment therapy on organizational commitment. Aims: The purpose of the present study was to determine the effectiveness of group counseling based on acceptance and commitment therapy on organizational commitment of staff of Gorgan Islamic Azad University. Method: This study was a quasi-experimental study with pre-test and post-test design with control group. The statistical population of this study consisted of all the administrative staff (except faculty members) of Islamic Azad University of Gorgan in the academic year of 2017-2018. 24 subjects were randomly selected and randomly divided into experimental and control groups Group 12) were replaced. Research tools include the Allen & Meyer (1990) Organizational Commitment Questionnaire and Flexman et al. (1970) acceptance and commitment group therapy counseling sessions. Data were analyzed using univariate analysis of covariance and multivariate analysis of covariance. Results: Group counseling based on acceptance and commitment therapy significantly improved the organizational commitment of the experimental group in the post-test phase, and group counseling based on acceptance and commitment therapy in improving the organizational commitment components of employees (emotional commitment)., Continuous commitment and normative commitment had a positive and significant effect (P< 0/01). Conclusions: Group counseling based on acceptance and commitment improved and enhanced organizational commitment of employees.