It is widely assumed that (1) children with challenging behavior may lack the social-emotional skills to be successful in classroom settings and (2) instruction in social-emotional skills can help prevent the occurrence of young children's challenging behavior. However, no data are available to indicate whether specific social-emotional skills might be most effective in reducing existing challenging behavior. In this study, we used an archival database to examine possible relationships between types of social-emotional instruction and changes over a 4-month period in levels of social skills and challenging behavior. The database, from a randomized trial of an intervention for preschoolers' challenging behavior, included measures of types of social-emotional instruction and children's social skills and challenging behaviors. Correlational analyses revealed statistically significant relationships between two types of social-emotional teaching practices and reductions in preschoolers' challenging behavior for children in the intervention group, "teaching children behavior expectations" and "teaching problem-solving." No other statistically significant associations were identified. The results are discussed in relation to possible implications for social-emotional instruction for preschool children already exhibiting challenging behavior and the value of further research focused on preventing challenging behavior in young children.