The relevance of business models for corporate performance in general and corporate sustainability in particular has been widely acknowledged in the literature while sustainable entrepreneurship research has started to explore contributions to the sustainability transformation of markets and society. Particularities of the business models of sustainable niche market pioneers have been identified in earlier research, but little is known about the dynamic role of business models for sustainable entrepreneurship processes aiming at upscaling ecologically and socially beneficial niche models or sustainability upgrading of conventional mass market players. Informed by evolutionary economics, we develop a theoretical framework to analyze co-evolutionary business model development for sustainable niche pioneers and conventional mass market players aiming at the sustainability transformation of markets. Core evolutionary processes of business model variation, selection and retention, and evolutionary pathways are identified to support structured analyses of the dynamics between business model innovation and sustainability transformation of markets.