In this article, the effectiveness of pre-service training that focuses on collaborative consultation and positive behavior support for treatment of challenging behaviors is evaluated. The effectiveness of an 8-month training program is evaluated for three participant groups: (a) 16 advanced undergraduate and master's-level students who received the training, (b) 16 classroom teachers who participated as consultees, and (c) 16 target children (4 to 10 years) who exhibited challenging behaviors that interfered with their learning. Multiple outcome measures are administered across two or three measurement times. Trainees demonstrate significant gains in knowledge, skills, and self-efficacy from pretraining to posttraining, and they have higher performance on three outcome measures at posttraining compared to a matched group of students who do not receive training. There are also significant gains for teacher consultees (knowledge and self-efficacy) and target children (behavior ratings and progress toward goals). Findings are discussed relative to study strengths and weaknesses, and implications for future research are identified. (Contains 6 tables.)