The aim of this study is to assess the relative efficiency of Iranian forest management units using the non-parametric method Data envelopment analyses (DEA). To this end, DEA as a well-known and robust technique for measuring the relative efficiency of organizations is used. The relative efficiency of comparable forest plans was calculated with the most frequently used DEA models – CCR, BCC and SE[LO1] . According to the results of global technical efficiency (CCR) and local pure technical efficiency (BCC), the efficiency averages were 0.83 and 0.93, respectively. The results of scale efficiency (SE) discussed a worrying aspect of these units’ efficiency; namely, there were only 3 efficient forestry plans (Shafaroud, Nav and Fiyab). However, using the Scale Efficiency Index (SEI) or FGL-DEA model brings out some interesting points; there were approximately 58% (7 units out of 12) under Increasing Returns to Scale (IRS). Thus, the managers of forest plans should more focus on forest plans under IRS so that they have the opportunity to become more efficient through growth, otherwise managers will not be able to promote their overall productivity.