The development of social and emotional competence is crucial for students. "Second Step" is a curriculum designed to promote prosocial development and prevent violence. The purpose of this study was to evaluate the effectiveness of implementing one unit of the Second Step curriculum (Impulse Control and Problem Solving). A controlled, repeated measures design was utilized to assess the level of change in knowledge of social-emotional skills. Results indicated that change was evident from pre- to post-test for third and fourth grade students (N=149). Third grade students receiving the intervention demonstrated significantly more knowledge growth than third grade control students. Notably, fourth grade students receiving the intervention demonstrated a similar level of knowledge growth as the fourth-grade control students. Discussion, limitations, and implications related to these findings are addressed. (Contains 4 tables.)