Global environmental change (GEC) threatens to undermine the sustainable development goals (SDGs). Smallholders in marginal mountainous areas (MMA) are particularly vulnerable due to precarious livelihoods in challenging environments. Acting collectively can enable and constrain the ability of smallholders to adapt to GEC. The objectives of this paper are: (i) identify collective actions in four MMA of the central Indian Himalaya Region, each with differing institutional contexts; (ii) assess the adaptive capacity of each village by measuring livelihood capital assets, diversity, and sustainable land management practices. Engaging with adaptive capacity and collective action literatures, we identify three broad approaches to adaptive capacity relating to the SDGs: natural hazard mitigation (SDG 13), social vulnerability (SDG 1, 2 and 5), and social-ecological resilience (SDG 15). We then develop a conceptual framework to understand the institutional context and identify SDG synergies and trade-offs. Adopting a mixed method approach, we analyse the relationships between collective action and the adaptive capacity of each village, the sites where apparent trade-offs and synergies among SDGs occur. Results illustrate each village has unique socio-environmental characteristics, implying distinct development challenges, vulnerabilities and adaptive capacities exist. Subsequently, specific SDG synergies and trade-offs occur even within MMA, and it is therefore crucial that institutions facilitate locally appropriate collective actions in order to achieve the SDGs. We suggest that co-production in the identification, prioritisation and potential solutions to the distinct challenges facing MMA can increase understandings of the specific dynamics and feedbacks necessary to achieve the SDGs in the context of GEC.