The paper seeks to contribute to the understanding of social innovation and entrepreneurship, with particular reference to the issue of hybridity. It builds on insights and categories accumulated in the existing literature on social innovation and entrepreneurship. The analysis identifies a hybridity criterion that is subsequently applied to the construction of a
more detailed and consistent social-forprofit hybrid spectrum than those proposed so far. It also identifies major theoretical challenges and suggests a generalized version of the hybridity criterion that may prove potentially fruitful to advance our understanding towards dynamic hybridity and multi-sectoral social innovation alliances.