This action research project was conducted to determine if using Second Step social emotional learning program would affect the frequency of negative behaviors in a preschool class. The lead teacher and associate were trained in Second Step social emotional learning. Second Step was implemented in the preschool class for three weeks. Qualitative data was collected from teacher interviews. Quantitative data was collected from behavior logs, behavior reports and researcher observations. The data was entered in a table and the data was used to determine if negative behavior decreased after implementing Second Step curriculum. After analyzing the data and teacher interviews, it was determined that implementing Second Step for a short period of time did decrease behaviors overall but, in some cases, increased negative behavior.