Empirical research shows that poor emotional competence is an early risk factor for the development of psychopathology. Numerous school-based prevention programs have been developed with the goal of decreasing behavior problems. Several of these programs include a discrete emotions component, but none of them are solely or primarily guided by emotion theory for their design and implementation. The prevention program described in this paper, the emotions course (EC), is a theoretically-coherent program based on differential emotions theory and is designed to be implemented by teachers in Head Start classrooms. Children participating in a pilot implementation of EC showed larger increases in emotion knowledge and less growth in negative emotion expression than their peers in control classrooms. These findings provide initial support for EC. Future implementations of the program need increased monitoring of implementation fidelity as well as additional methods to assess the success of the program.