Achieving regulatory compliance, a 360 degree view on customer data, and an effective and efficient reporting are critical business requirements that can be traced back to a high quality of IT and data resources. Addressing these requirements, the regulation of decision rights and accountabilities for organisational decision-making about IT and data assets has become a key success factor for organisations. The aim of this paper is to analyse the performance impact of a combined IT and data governance concept. The study uses the resource-based perspective and integrates the theory of complementarities and the concept of relatedness. The proposed increase in business process performance is grounded in the generation of sustainable competitive advantages. The framework is developed by using nine exploratory case studies in multi-business organisations. The results suggest that IT and data governance are positively related with business process performance through the mediators of IT relatedness and data relatedness.