Given the importance of the strategic pistachio crop and the necessity of developing pistachio growers’ knowledge, attitude, and skills, the project of timely management for pistachio orchards has been implemented by the Educationand Extension Departmentof the AREEOin 13 pistachio-growing provincesby creating comprehensivemodel sites. Considering theimportance and continuity of thisplan, evaluating its effectivenessis crucial. Accordingly, inspiredby the Kirkpatrick model, thisquantitative research was conducted toevaluate theeffectiveness of model sites in changing the behavior ofpistachio growers. Thestatistical population of the researchwas 31 model sites from which28 model sites completed thequestionnaires. Validity of the questionnairewas verified by a panel of experts and computingAVE, and its reliability wasconfirmed by Cronbach'salpha and composite reliability.Data was analyzed usingSPSSwin26 and Smart PLS3 software.The findings revealed that themean score of the instructions in termsof process characteristics (relevancyto theneeds of gardeners, feasibility, and financial feasibility) is 4.10 out of 5. The mean score of the instructions application in the fieldwas equal to 3.92. Reducing farmers' mistakes, making more appropriate decisions, and increasing the yieldwere theitems with the most behavioral change. In the contextof project other agricultural impacts, optimal pesticide consumption, the pesticides consumption reduction of and chemical fertilizers optimal application, and in the context of other social and extension impacts, improving the attitude of gardeners towards scientific gardening, improved interaction between gardeners, extension agents and researchers and improving the attitude of gardeners towards extension agents had the highest averages. The sites was successful in the diffusion of the instructions, with a mean score of 3.93 out of 5.