While knowledge transfer is one of the key components in determining Mergers and Acquisitions (M&A) success, the current M&A literature has produced inconsistent findings regarding its antecedents and consequences. To address this research gap, this study explores the roles of functional integration and shared goals in facilitating knowledge transfer, which will in turn determine M&A success. To provide a more nuanced understanding of knowledge transfer, this study examines bilateral knowledge flows (e.g., knowledge transfer to a target firm from the UK acquiring firm and knowledge transfer from a target firm to the UK acquiring firm). Our research framework is built upon two different theoretical perspectives, namely resource orchestration and social capital theories. Our propositions were tested empirically across a sample of 131 UK cross-border M&A firms. Our results reveal that the affirmative roles of functional integration and shared goals in increasing knowledge transfer both to and from a target firm are confirmed and that knowledge transfer to the target firm is deemed decisive for M&A success. Based on the findings, we discuss theoretical and practical implications, followed by limitations and future study consideration.