Mergers and acquisitions continue to be prevalent despite frequently yielding disappointing outcomes. Post-merger integration plays a critical role in M&A success, yet many questions about M&A implementation remain unanswered. We review research on post-merger integration, which we organize around key themes of reconfiguration and renewal; culture; identity; justice; trust; and learning. We lay out a research agenda that centers on understanding and explicating dynamic processes. We focus on opportunities related to temporality; emotions; practices, tools and learning; networks; and decision-making processes.