Purpose: This paper identifies socio-ecological stewardship competences that smallholder farmers in the Manafwa watershed in Eastern Uganda, developed by participating in a project founded on the Participatory Integrated Planning approach. Methodology: A case study approach was applied. Data were collected by interviewing smallholder farmers and PIP trainers; observing farm practices and PIP training sessions; and conducting focus group discussions. Data were analysed thematically, inspired by the environmental competence model of Roczen, to identify socio-ecological stewardship competences. Findings: The study identified socio-ecological stewardship competences comprising different sustainability-related dimensions including: 'environmental knowledge' as environmental systems, action-related, effectiveness, social, and ethical knowledge; 'connection with nature' as establishing an identity with nature, appreciating the value of nature, social, and ethical attitudes; and 'ecological behaviour' as conservation and restoration, social, and ethical actions. Practical implications: Competence dimensions are interconnected thus requiring learning environments that develop them simultaneously. Additionally, social and ethical competences are relevant for supporting stewardship action. Theoretical implications: This study expands Roczen's environmental competence model by including social, ethical, and conservation and restoration action competences. Originality/value: This study is the first to identify socio-ecological stewardship competences and the learning processes that can foster these competences.