The Check-in/Check-out (CICO), developed as a Tier 2 intervention program within the scope of positive behavior support in the literature, is suggested for the students with unsatisfactory peer relationships as well as low academic achievement and problem behaviors. The aim of this study is to evaluate the effectiveness of the CICO program on active participation to lesson behavior of the students who display problem behaviors and have low academic achievement in the dassroom. In this study, the behavior of the students' effective participation to lessons was examined. Three 10-11 year-old secondary-school students participated in the study. Range-bound changing criterion design, which is one of the single subject experimental designs, was used throughout this study. The feedback gained from the teachers and the students indicated that the students improved in the behavior of effective participation to lessons. Social validity results are also consistent with the social relevance of the independent variable and the results of the study.