Critical realism provides an ontological foundation for theories of business markets. Critical realism contributes to business marketing theory by (1) proposing an open systemapproach as a response to the limitations of empirical observation for uncovering causalmechanisms shaping business markets, (2) revealing the interaction of social structures and subjective agency in shaping professional buying processes and (3) revealing emergent properties of business relationships, where interacting businesses create value that no individual company could produce in isolation. Critical realism paves the way for researchers aiming to transcend the limitations of middle-ground theories and thriving for higher-levels of generalization. Thus, critical realism offers a response to the call of marketing scholars for approaches revealing a more general understanding of the role of business markets in the context of emerging networked economies