Digital technologies and related capabilities, such as business analytics capabilities (BAC), are transforming firms and management control (MC). While the development of BAC and its underlying dimensions is currently a top priority for many MC departments, it remains unclear from the existing literature how they can benefit from these capabilities in terms of controllership effectiveness. Against this background, our study examines the relationships between three core BAC dimensions (tangible BA resources, intangible BA resources, and human skills for BA) and controllership effectiveness (in terms of controllership output quality and controllership impact on management decisions), with a particular focus on the mediating effects of the business partner role of the MC department. To do so, we adopt the resource-based view and use partial least squares structural equation modeling (PLS-SEM) to analyze survey data from 322 large German firms. The results of our study show that all of the examined relationships are positively mediated by the business partner role, while those between tangible BA resources and both elements of controllership effectiveness, as well as that between human skills for BA and controllership impact on management decisions are even fully mediated by this role. Thus, our results highlight the importance of the business partner role in enabling MC departments to benefit from the development of the BAC dimensions in terms of improved controllership effectiveness. Furthermore, through a series of post hoc analyses, we provide empirical support for our three-dimensional conceptualization of BAC, and for the importance of the business partner role relative to the still dominant scorekeeper role. Theoretical and practical implications are discussed.