This chapter illustrates the livelihood adaptation strategies of migrant informal workers in cities from a social innovation lens. It focuses on the characteristics of informal entrepreneurship as adaptive innovation. The chapter demonstrates the agency and creative potential of informal migrant workers as active subjects in innovations and making appropriations of their own. Adaptive innovations are social innovations that are context-specific, developmental and always committed to the values of social justice and environmental sustainability. The chapter presents the view that adaptation strategies of migrant informal workers need to be seen as a social, economic and political process and not as a mere technical exercise. Interactions with migrant workers revealed adaptation strategies through mobility, livelihood diversification, risk pooling, asset conservation, storage and enhancement, self-remedy, market exchange, structural adaptation and informal entrepreneurship. The chapter discusses each adaptation component in detail.