This study examines the effectiveness of fixed-time (FT) and variable-time (VT) schedules and attention on the problem behaviors and on-task behaviors of students with and without intellectual disabilities in inclusive classrooms in Turkey. Three second-grade students with intellectual disabilities, three students without intellectual disabilities, and three teachers participated in this study. The ABAC reversal design of the singlesubject design was used. A1 and A2 were the baseline conditions; in the B condition, an FT schedule of attention (every four minutes) was implemented, and in the C condition, a VT schedule of attention (average four minutes) was utilized. The results demonstrated that FT and VT schedules of attention decreased problem behaviors, and increased on-task behaviors during lessons. Moreover, in the VT schedule of attention, gains were noted to be faster and more consistent, and teachers performed VT more easily