This paper explores the role of customer engagement behavior (CEB) in value co-creation within a multi-stakeholder service system, focusing on a public transport service system involving consumers, communities, businesses, and governmental organizations. The authors identify four types of CEB: augmenting, co-developing, influencing, and mobilizing. Augmenting behavior involves customers contributing resources to directly enhance the firm's offering. Co-developing behavior involves customers providing resources to facilitate the firm's development. Influencing behavior involves customers affecting other actors' perceptions and preferences. Mobilizing behavior involves customers inducing concrete actions towards the firm by mobilizing other stakeholders. The study finds that CEB affects value co-creation by modifying and augmenting the offering, and influencing other stakeholders' perceptions and actions. The paper proposes nine research propositions to explain the connections between CEB and value co-creation, emphasizing the importance of resource integration and the broader impact of CEB on the system level.This paper explores the role of customer engagement behavior (CEB) in value co-creation within a multi-stakeholder service system, focusing on a public transport service system involving consumers, communities, businesses, and governmental organizations. The authors identify four types of CEB: augmenting, co-developing, influencing, and mobilizing. Augmenting behavior involves customers contributing resources to directly enhance the firm's offering. Co-developing behavior involves customers providing resources to facilitate the firm's development. Influencing behavior involves customers affecting other actors' perceptions and preferences. Mobilizing behavior involves customers inducing concrete actions towards the firm by mobilizing other stakeholders. The study finds that CEB affects value co-creation by modifying and augmenting the offering, and influencing other stakeholders' perceptions and actions. The paper proposes nine research propositions to explain the connections between CEB and value co-creation, emphasizing the importance of resource integration and the broader impact of CEB on the system level.