CODEOWNERS is a GitHub file that maps files or folders to their owners, automating the right notifications and approvals. It shapes how engineering teams collaborate, take responsibility, and move faster by driving accountability through ownership. Ownership leads to high-quality code, reduces ambiguity in code boundaries, and enables faster incident response. To wield CODEOWNERS strategically, align ownership with team boundaries, limit ownership scope to empower teams, keep ownership fresh and up-to-date, use it to onboard and educate new engineers, and measure its impact by tracking key signals such as review times and qualitative feedback. Understanding different styles of code ownership is crucial for tailoring processes to fit the team's needs. Common ownership challenges include catch-all owners, stale ownership, over-reviewing, and siloed ownership, which can be tackled through regular audits and guidelines. By implementing CODEOWNERS effectively, teams can improve their development experience and collaboration.