"First Step to Success" is an early intervention program designed to help children who are at risk for developing aggressive or antisocial behavioral patterns. The program uses a trained behavior coach who works with each student and his or her class peers, teacher, and parents for approximately 50 to 60 hours over a three-month period. "First Step to Success" includes three interconnected modules: screening, classroom intervention, and parent training. The screening module is used to identify candidates who meet eligibility criteria for program participation. Classroom intervention and parent training comprise the program intervention component of "First Step to Success". Two studies of "First Step to Success" that fall within the scope of the Children Classified as Having an Emotional Disturbance review protocol meet What Works Clearinghouse (WWC) evidence standards, and no studies meet WWC evidence standards with reservations. The two studies included 243 children in kindergarten through third grade who attended schools in New Mexico and Oregon. Based on these two studies, the WWC considers the extent of evidence for "First Step to Success" on children classified with an emotional disturbance (or children at risk for classification) to be small for all domains examined in this report (external behavior, emotional/internal behavior, social outcomes, reading achievement/literacy, and other academic performance domains). Appended are: (1) Research details for Walker et al., 1998 and for Walker et al., 2009; (2) Outcome measures for each domain; (3) Findings included in the rating for the external behavior domain, the emotional/internal behavior domain, the social outcomes domain, the the reading achievement/literacy domain, and the other academic performance domain; and (4) Single-Case Design studies reviewed for this intervention. A glossary of terms is included. (Contains 21 tables, 15 endnotes and 3 additional resources.)