Data governance is the organizational discipline of managing data as an asset. It establishes policies (data ownership, retention, access), processes (data catalogs, metadata management, audits), and tools (governance platforms) to ensure data quality, compliance, and alignment across the organization. Example: "We own 200 datasets. Who's responsible for each? What quality standards apply? Who can access PII? How long do we keep data? If a dataset breaks, who needs to know?"