Eastern African countries have been confronted with forest landscape degradation and the consequently growing gap between the supply and demand of wood products. Small-scale farmers growing trees on farm have been increasingly acknowledged as a major wood supplier. Value chain analysis studies pointed out the challenges faced by the smallholders, as they are commonly engaged in informal wood markets, associated with weaker bargaining power and market asymmetry. From the Social and Solidarity Economy lens, collective action approaches through farmers’ organizations can counter the challenges of individual smallholders, while facilitating the upgrading of wood value chains. Thus, the objective of this dissertation was to analyze the (potential) roles of forest farmers’ organizations (FFOs) in wood value chain upgrading, with two case studies in Ethiopia and Tanzania. Through a systematic literature review worldwide, the study first sought to provide a knowledge base for FFO research grounded on (i) the policy context within which FFOs operate, and (ii) the typology of their performance with reference to resource mobilization, commercialization of wood products and benefit sharing mechanisms. Value chain analyses of wood products from smallholders each in Ethiopia and Tanzania were the point of departure for the empirical work, consequently treated as the case studies. A collective of smallholders and individual smallholders were embedded as the units of analysis in the two independent case studies. The two-country study setting permitted the analytical generalization of collective action approaches to value chain upgrading and the development of a research agenda and policy recommendations. Grounded on the value chain upgrading approach, FFO business models were co-developed to assess the interlinkages between the business model and (i) the organizational governance and (ii) the implications on wood value chain upgrading. Participatory workshops with existing farmers’ organizations were conducted to co-develop the business models, while focus group discussions and key informant interviews served to frame and triangulate the contextual conditions. Semi-structured household interviews were employed to examine the perception of FFOs and the main factors influencing farmers’ willingness to participate. Binary logistic regression analysis and descriptive statistics were employed in tandem with thematic analysis to analyze the data. The global review represented 57 FFOs distributed globally across 20 countries, which were manifested as associations, cooperatives, and small- and medium-sized enterprises. Research in FFOs has gained scholarly traction in the last three decades, emphasizing the emerging trend of smallholders managing forest farm forestry plots across the tropics. The review revealed three categories of FFOs, depending on the extent of the organization’s product portfolio, the value addition captured at the organizational level, and the linkages to market channels. The empirical findings revealed that southern Ethiopia and southern Tanzania had contrasting regulatory framework for the establishment of FFOs. Given the existing foreign donor program targeted at smallholders in Tanzania, institutional and financial start-up support exist. In both cases, farmers were able to envisage an FFO business model that would allow product and process upgrading of wood value chains. The FFO was perceived differently across the two cases. The Ethiopian case study referred to it as a tree marketing cooperative, which shall facilitate the production of members’ woodlots and the commercialization of wood products of members and non-members alike at a timber yard in a nearby urban area. The Tanzanian case study termed it as a tree growers’ association, which shall facilitate the production of members’ wood and non-wood products, and the commercialization of members’ sawn timber to existing traders. Achieving functional upgrading would necessitate concerted efforts by various governmental and non-governmental stakeholders. The household interviews revealed that 74% (n = 185) and 90% (n = 190) of smallholders would be willing to participate in an FFO in the Ethiopian and Tanzanian case, respectively. In Ethiopia, farmers perceived it as a collective wood marketing enterprise. A relatively small group size with substantial monetary contribution characterize farmers’ preferences to undertake a joint business on wood marketing. In Tanzania, the perception of a tree growers’ association centered on social learning elements to improve wood production and find alternative buyers, while regulating fire incidences. In both cases, the significant factors influencing farmers’ willingness to participate were (1) household socio-economic characteristics, e.g. household head’s age group or household size; and (2) experiences with tree growing activities, e.g. price satisfaction in the last sales or difficulty in market access. The synthesis permitted the derivation of the following conceptual assertion: that FFOs have the potential in upgrading the wood value chains, as long as farmers can envision a business model of an FFO that accommodates the factors influencing farmers’ willingness to participate. Overall, the study demonstrates the changing narratives of farmers’ organizations in the study countries and contributes to the commons-cooperative alliance theory – the integration of collective action and cooperative management. Furthermore, the key findings provide the groundwork to springboard future research avenues, specifically to test the derived assumptions, and recommendations for policy and development.