Castle Rock Elementary is an International Baccalaureate Primary Years Programme school and a California Distinguished School serving 516 students from kindergarten through fifth grade. It is a part of Walnut Valley Unified School District and borders the 57 Freeway in south Diamond Bar. The school also shares a border with Heritage Park.
The IB Primary Years Programme identifies a specific curriculum to which the school adheres. From 2009 to 2010, Castle Rock's Academic Performance Index score rose 2 points from 923 to 925 (on a scale of 200 t0 1,000). Its mascot is the Knight.