<p>Self-sufficiency has long structured the livelihoods of the Mising community of Sikom, a river island in Assam, through subsistence agriculture, traditional healing, and localized resource management. Drawing on qualitative fieldwork, this study critically examines whether self-sufficiency, under conditions of infrastructural isolation, market exclusion, and climate stress, can sustain long-term resilience. The findings show that while indigenous practices ensure household-level survival and cultural continuity, their sustainability is increasingly undermined by external constraints, including limited access to markets, healthcare, education, and climate-adaptive infrastructure. Rather than framing self-sufficiency as inherently restrictive, the paper argues that its vulnerabilities emerge from structural marginalization and environmental precarity. The study concludes that sustainability in indigenous contexts requires a hybrid approach that strengthens indigenous knowledge while addressing systemic exclusions through targeted state support, market linkages, and climate adaptation measures.</p>