Both corporate social responsibility (CSR) and diversity determine firms’ value creation, yet their relationship and their link to innovation remain uncertain, especially among small to medium-sized enterprises (SMEs). With a strategic perspective, this article proposes that CSR strategies might be vehicles for promoting firm diversity, which triggers innovation. In an analytical framework, the authors consider two types of CSR (strategic versus responsive) and two types of diversity (gender and nationality). The results from a sample of 1348 SMEs from Luxembourg show that strategic CSR encourages both gender and nationality diversity, but responsive CSR does not. Both types of diversity favor SMEs innovation. Thus, only strategic CSR, through the genuine integration of diversity, can help SMEs achieve value-in-diversity.