Innovation is widely recognized as a key asset for firms, positively affecting performance, growth, long-term value creation, and competitive advantage. When studying innovation, scholars usually focus on large and listed firms, while relatively limited knowledge exists on innovation in family firms and small and medium-sized enterprises (SMEs). However, these are the most ubiquitous forms of business organization around the world and overlooking their distinctive features may limit current understanding about innovation. In this chapter, we highlight relevant research avenues and unaddressed questions for future research on innovation in family firms and SMEs. In so doing, we outline a future research agenda that will hopefully guide future scholars interested in innovation in the context of family firms and SMEs.