We empirically examine social innovation and openness through a survey of social enterprise hybrids in the United Kingdom (UK). Social innovation refers to new products, processes and services that respond to grand challenges. Social enterprises pursue economic, social and environmental goals but vary in their goal orientation, namely the relative importance ascribed to such goals. We first explore the relationships between commercial, social and environmental goal orientation and social innovation performance. Next, we consider the moderating impact of openness to external knowledge and ideas on social innovation performance. Our analysis finds positive and significant relationships between commercial and social goal orientation and social innovation performance, but no relationship with environmental goal orientation. In addition, the use of external sources of knowledge and ideas positively strengthens these relationships for both commercial and social goal orientation but not for environmental goal orientation. Our results reveal some important influences on social innovation, openness, and hybrid organizing.