The present study examined teachers’ knowledge, frequency of use, and confidence in identifying, preventing, and intervening in relational aggression in their classrooms and schools. A teacher training was implemented and evaluated using followup surveys in a pre-test/post-test design. Participants were middle school teachers from 11 city and county schools in the Southeast region of the United States. Knowledge and frequency of use were assessed through an adapted form of the Teacher Inventory of Skills and Knowledge (Newman, Horne, & Bartolomucci, 2000). Teacher confidence was assessed using measures developed by Goryl, Neilsen-Hewett, and Sweller (2013). This design included two survey points. Teachers received the first survey on self-perceived knowledge, frequency of use, and confidence related to relational aggression as a way to collect baseline data. Three-months after the teacher training, a second survey was evaluated long-term effects. Teachers initially reported high levels of total knowledge and total frequency of use, but generally lacked confidence. Another important distinction was gender. Results indicate males’ self-perceptions of their knowledge, frequency of use, and confidence related to relational aggression is higher than female counterparts. This is consistent with other literature on self-perceived confidence and gender (Colbeck, Cabrera, and Terenzini, 2000). Both confidence and knowledge increased for teachers who participated in the targeted in-service training while there was no effect on confidence for the control group. This supports past research (Bowllan, 2011; Olweus et al., 2002).