Purpose: Considering current debates on ecosystem services' effectiveness and the AIS/AKIS functioning, in this study we suggest a new, systemic way to evaluate extension systems (ESs). Using this model, we compared the effectiveness of ESs in three countries with essential differences but also characteristic similarities in their agricultural sectors: Greece, Italy and Slovenia.Design/methodology/approach: Initially, we defined 'extension system' as a wide range of actors integrating resources with the aim of co-producing value (not for but with) farmers. To capture the value flow within this constellation of actors we distinguished between the notion of 'value in production' -- i.e. the value embodied in service offerings -- and the value emanating when service content is used in real settings or 'value in use.'Findings: Our approach revealed that, despite their structural and organizational differences, the ES in the three countries share common problems arising from a limited focus on the issue of value in use. Practical implications: The application of a systemic approach -- seeing farmers as co-creators and not as end-users of extension services -- in the evaluation of ESs contributes to better understand the complexity of value flow within the system and can strengthen extension systems' effectiveness.Theoretical implications: The present study, by reconsidering traditional evaluation approaches and by focusing on value co-production, offers an alternative value-centric framework for the conceptualization of extension services and points out to the need for refining the evaluation criteria of ESs.Originality/value: Our work, by emphasizing the reciprocal creation of value within ESs, and by adding the concept of value in use, offers a new systems approach worth considering when evaluating ESs within different organizational and sociocultural contexts.