In this introduction to the special issue on business model innovation (BMI) among social purpose organizations (SPOs), we define business models, BMI, and SPOs, and introduce the insights that papers in this special issue contribute to scholarly knowledge at the intersection of SPOs and BMI. We aggregate insights from articles in the special issue to provide insights into the major antecedents of BMI (environmental turbulence, and internal drivers), the substance of BMI (collaboration, managing tensions, and developing dynamic and learning capabilities), and the outcomes of BMI (expansion of dual social-economic goals, and organizational survival). Reflecting on this collection of papers, and the broader social sector literature, we then suggest several avenues for future research.