In most production environments, database and server optimization have long been the domain of DBAs. This includes server settings, hardware optimizations, index creation and maintenance, and many other responsibilities. SQL developers, however, are responsible for ensuring that their queries perform optimally. SQL Server is truly a developer’s DBMS, and as a result the developer responsibilities can overlap with those of the DBA. This overlap includes recommending database design and indexing strategies, troubleshooting poorly performing queries, and making other performance-enhancement recommendations. This chapter discusses various tools and strategies for query optimization and performance enhancement and tuning queries.