Regarding the sustainable schemes, green building may be considered as an alternative for managing the energy use in developing countries such as Iran. Investigating green factors in the other systems, the aim of the present study was to propose a new set of comprehensive factors suits assessing green buildings and to evaluate them in the Iranian context to contribute a new aggregated rating tool for offices. Therefore, 8 major and 61 minor stakeholders were defined to cover all required criteria respecting previous studies, expert opinions and questionnaire forms. The defined criteria were weighted using multi criteria decision methods consisting of analytical hierarchy process, weighted harmonic mean and Shannon's entropy. Then, Iranian Green Building assessment Tool (IGBT), consisting five certification levels, was developed based on weighted factors to improve environmental, social and economic aspects in the construction process. After that, aggregating IGBT, Geographical Information System (GIS) and multi-criteria decision methods, the practical application of the proposed tool was implemented on 48 offices through a case study in the municipality of Mashhad, Iran. For this purpose, a spatial database of 612 land uses was prepared to determine certification levels of the office buildings in the study area. The assessment procedure, applied in GIS, demonstrated five certified office buildings. Results of designing IGBT showed that the energy efficiency and the water efficiency, with the total score of 39%, are the most significant factors for assessing green office buildings with respect to the vital circumstances of energy and water conservation. Also, comparing performance sensitivity to the five representative green building rating systems confirmed the reliability of the suggested tool based on measuring the criteria deviations. The outcomes provide a valuable reference to the policy makers in Iran and also could be a considerable suggestion to the future studies. (C) 2016 Elsevier Ltd. All rights reserved.