Very few of the many innovations proposed by research have been adopted by family farms. The main reason is that these innovations are out of step with the technical, economic and organizational needs of farmers. We assume that the establishment of a partnership between the actors of family farming systems and research is essential to overcome this difficulty. This chapter’s goal is to discuss the usefulness of this principle basing ourselves on three sets of interventions in Burkina Faso, Cameroon and Brazil. Action research in partnership born of the encounter between a desire for change (expressed by field stakeholders) and a willingness to explain the causes and processes of change (supported by research). It takes place in three phases. Exploration and Formalization of partnership (Phase 1) begins with a diagnosis (situation analysis and problem setting) and the establishment of local committees. At this stage, the actors sign contracts an action program (specifications). Co-design innovation (phase 2) is based on three iterative steps (exploration potential > selections of options in accordance with the reasons actors > implementation on farms and territories, monitoring and selection of the most efficient options). During phase 3 (Reviewing the results and Disengagement), the work consists of: (i) publish actionable knowledge produced; (ii) make available the solutions validated by experiments to the stakeholders; (iii) to assess the impacts (solutions, stakeholder capacity, etc.).