This chapter examines how cooperative performance should be evaluated and how legal–institutional ecosystems can support cooperative development. It argues that conventional performance indicators used for investor-owned firms (e.g., sales, profit, ROI) are insufficient for cooperatives because cooperative outcomes occur not only at the enterprise level but also at the member and social levels. In producer cooperatives, for example, performance should reflect improvements in members’ income, stability, and productivity, not just the cooperative’s financial results. Profitability indicators must be interpreted carefully, since pricing and wage policies directly affect member welfare. The chapter highlights the diversity of cooperative social performance. Cooperatives can reduce market failures such as information asymmetry, provide essential services where markets are absent (e.g., in rural areas), strengthen community cohesion, build social trust, and mitigate income inequality—especially through worker, social, and community-oriented cooperatives. Because many cooperative benefits resemble public goods and externalities, market forces alone tend to underprovide cooperative activity. International bodies such as the UN and ILO therefore emphasize the need for cooperative-specific legal, tax, financial, and entrepreneurial support systems. Key policy elements include clear legal recognition of cooperative identity (mutuality, democratic control, solidarity), tax systems that recognize indivisible reserves and solidarity funds, cooperative-based financial institutions, and entrepreneurship ecosystems tailored to cooperative start-ups. Finally, the chapter reviews cooperative development in Africa, Latin America, and Southeast Asia. It shows that sustainability depends less on the number of cooperatives and more on governance capacity, market integration, legal enforcement, and long-term institutional support.