During the COVID-19 crisis, small and medium-sized enterprises (SMEs) in developing markets, marred by significant institutional voids, grappled with a perennial lack of resources. This article seeks to understand how these SMEs activated their dynamic capabilities to manage business relationships during different phases of the crisis. Relying on the social exchange theory and drawing on semi-structured interviews with 42 business-to-business (B2B) SME owners in Nigeria, we examine the relational governance mechanisms of dynamic capabilities for SMEs during the COVID-19 crisis. Our findings reveal 12 relational governance mechanisms of dynamic capabilities of B2B SMEs. Furthermore, we disaggregate these 12 mechanisms into 34 relational governance micro-foundational components and demonstrate their relevance for B2B SMEs during different stages of the COVID-19 crisis in Nigeria.