Query Store is a built-in SQL Server feature (2016+) that automatically captures query execution history, plans, and runtime statistics—enabling performance analysis and plan forcing without third-party tools. Available in all SQL Server editions including Express and Azure SQL Database. Key capabilities include automatic plan regression detection, A/B testing of execution plans, plan forcing to lock in good plans, and historical performance trending. The feature stores query text, execution plans, and runtime statistics (CPU, duration, reads, writes) with configurable retention. Plan forcing enables DBAs to override optimizer decisions when regression occurs. Query Store is the foundation for Automatic Tuning in SQL Server 2017+, which can automatically revert plan regressions. Page should cover: enabling and configuring Query Store, interpreting Query Store reports, plan forcing best practices, Automatic Tuning integration, Azure SQL Database specifics, and comparison with third-party monitoring tools.