Introduction The olive tree is one of the earliest domesticated crops in human history and has played an enduring cultural, economic, and nutritional role across civilizations. Archaeological evidence and the presence of centuries-old olive trees from western to northern Iran attest to the long-standing significance of olive cultivation in the region. Globally, olive production spans approximately 11 million hectares, while Iran accounts for nearly 80,000 hectares, producing about 237,000 tons annually. Within Iran, Gilan Province ranks second in cultivated area and is a major contributor to national olive production, with Rudbar County recognized as the historical epicenter of the country’s olive and olive oil industries. The quality and quantity of olive oil are highly dependent on appropriate post-harvest practices, including optimal harvest timing, suitable transportation, proper fruit storage, and minimal delays between harvest and processing. Poor post-harvest handling—such as storing olives in non-ventilated plastic bags or prolonged waiting times before processing—can elevate acidity levels and accelerate oxidative degradation. Compounding these issues, many small-scale farmers harvest olives prematurely for table olive markets due to limited awareness of the economic and technical benefits associated with full maturity harvest for oil production. Despite the crucial role of training in improving technical performance within agricultural value chains, little attention has been paid to the specific impact of training delivered directly by olive oil extraction units. These units represent a pivotal link between farmers and processing facilities and are uniquely positioned to influence farmers’ knowledge about best practices, including harvesting methods, storage protocols, and delivery standards. Yet, no systematic assessment has been conducted on how their training affects oil yield, oil quality, or farmer satisfaction. Given Rudbar County’s distinct status as the central hub of olive cultivation and processing in Iran—and the prominent role of private extraction units as de facto extension providers—it is essential to investigate their effectiveness in transferring technical knowledge. Furthermore, service quality affects farmers’ willingness to adopt recommended practices, making the SERVQUAL model an appropriate tool for evaluating perceived performance and expectations. Consequently, this study seeks to assess the effects of training conducted by olive oil extraction units on oil yield and oil quality, and to evaluate farmers’ satisfaction with service quality. By comparing trained and untrained farmers and identifying key service quality gaps, the study provides evidence-based insights that can inform more effective extension strategies, strengthen the operational performance of extraction units, and enhance the overall efficiency and competitiveness of the olive value chain in Rudbar County. Materials and methods This research was conducted in Rudbar County, Gilan Province, from 2021 to 2023 to evaluate the effects of training provided by olive oil extraction units on oil quantity, oil quality, and farmer satisfaction. A comparative design was employed, involving a group of farmers who received structured, face-to-face instruction by technicians and operators of the extraction units and a control group with no formal training. Four extraction units with the highest levels of farmer engagement constituted the study population. Sampling followed a two-stage process. First, stratified sampling with proportional allocation was used to determine sample shares for each extraction unit. Second, simple random sampling was employed to select participants within each stratum. Based on the Krejcie–Morgan sampling table, a minimum of 243 farmers was required; ultimately, 243 farmers were included, split evenly between trained and untrained groups. Training sessions lasted approximately two hours and covered optimal harvest timing, recommended fruit handling methods, appropriate delivery intervals, and fundamental oil extraction principles. Oil quantity was measured using yield per hectare and statistically compared between groups using independent-samples t-tests. Oil quality was assessed through laboratory analyses of acidity and peroxide values, following national standards ISIRI 4178 and ISIRI 4179, respectively. Farmers' satisfaction with service quality was evaluated using a 23-item SERVQUAL questionnaire covering reliability, responsiveness, empathy, assurance, and tangibles. Both perceived performance and expectations were rated on five-point Likert scales, and service quality gaps were computed by subtracting performance scores from expectation scores. Content validity was confirmed through expert review using the Content Validity Index (CVI), and reliability was tested via Cronbach’s alpha, which exceeded the minimum threshold of 0.70 for all dimensions. Data were collected on-site at extraction units during the processing season to ensure response accuracy. Analyses included descriptive statistics, independent-samples t-tests, Pearson correlations, and Wilcoxon signed-rank tests using SPSS version 26, with the significance level set at 0.05. Results and discussion Of the 243 participating farmers, 89% were male and most were between 30 and 50 years old. Over half held university degrees and had more than five years of farming experience, suggesting considerable potential for adopting improved production practices. When comparing oil yield, trained farmers consistently produced lower yields than untrained farmers, a difference that reached statistical significance only in the Baghdaran unit. This reduction is attributable to earlier harvesting among trained farmers—a practice known to decrease extraction volume while enhancing oil quality through improved phenolic content and reduced oxidative deterioration. Regarding oil quality, no significant differences emerged in acidity levels between the trained and untrained groups, and all samples met the criteria for virgin olive oil. However, peroxide values were significantly lower among trained farmers in the Baghdaran unit, indicating improved oxidative stability resulting from better post-harvest handling. The lack of comparable improvements in other units suggests variability in training quality, inconsistent reinforcement of recommended practices, or operational shortcomings within processing facilities. Quality classification showed that most oil samples fell within the “ordinary virgin” category. Notably, only trained farmers from the Golestan Zeytoon unit achieved “fine virgin” status, underscoring the combined importance of proper farmer practices and well-maintained extraction infrastructure. The SERVQUAL analysis revealed significant negative gaps across all dimensions—reliability, responsiveness, empathy, assurance, and tangibles—indicating that farmers’ expectations were not met by the services provided. The most substantial gap occurred in responsiveness, reflecting dissatisfaction with the timeliness, clarity, and adequacy of information and assistance provided by staff. This gap suggests weak communication practices, insufficient customer service training, and inadequate managerial oversight. Tangibles, including equipment and physical facilities, also showed negative gaps, pointing to a need for modernization and better maintenance. Taken together, the findings highlight the complex interplay between farmer behavior, training effectiveness, and extraction unit performance. While training has demonstrable potential to improve oil quality, its impact remains limited unless complemented by improvements in operational management, staff competencies, and standardized service protocols. The absence of a formal oversight mechanism further exacerbates inconsistencies among extraction units, limiting the effectiveness of decentralized, non-governmental extension services. Conclusion This study demonstrates that olive oil extraction units in Rudbar County possess significant potential to enhance both oil quality and farmer satisfaction through well-designed training and improved service delivery. Training contributed to measurable improvements in peroxide values within at least one unit, confirming the effectiveness of practices such as timely harvesting, proper fruit handling, and reduced post-harvest delays. Although earlier harvesting led to a modest decline in oil yield, the resulting improvements in oil quality—and the potential for higher-value classification—suggest an overall benefit to farmers and the olive value chain. However, the pervasive negative service quality gaps across all SERVQUAL dimensions indicate that current service delivery does not meet farmers’ expectations. The most critical shortcomings relate to responsiveness, including the timeliness and clarity of communication and staff willingness to assist. These deficiencies, if unaddressed, may erode farmers’ trust in extraction units and reduce participation in oil extraction activities, potentially shifting production toward lower-value table olives. To improve outcomes, extraction units must adopt a more integrated approach that aligns technical training with managerial reforms and stronger service orientation. Establishing a formal cooperative or industry association could provide the oversight needed to ensure consistent service delivery standards. Regular monitoring by provincial food and drug authorities—particularly during the oil extraction season—would help ensure compliance with technical and sanitary requirements. Introducing a differentiated pricing system based on oil quality could further incentivize farmers and extraction units to adopt best practices. Overall, enhancing the effectiveness of training, improving service quality, and strengthening regulatory coordination will contribute significantly to upgrading the performance, economic viability, and sustainability of the olive value chain in Rudbar County.