Teaching verbal mathematics problem-solving skills to individuals with developmental disorders is important for these individuals to understand cause and effect relations. The present study aimed to determine the effectiveness of a schema approach for individuals with Autism Spectrum Disorders (ASD) acquiring and sustaining verbal mathematics problem-solving skills. The study also aims to investigate the participants’ verbal mathematics problem-solving skills, their retention levels after the termination of the application, and generalization of this skill to different types of mathematics problems. Three individuals with ASD aged 9, 11, and 14 participated in the study. A single-subject, multiple-probe design with probe conditions across participant research method was used. The findings demonstrated that instruction with the schema approach increased the participants’ verbal mathematics problem-solving performance. This increase was retained 1, 3, and 5 weeks after the instruction was completed. Furthermore, two participants were able to generalize the verbal mathematics problem-solving skills for comparison-type problems with unknown results in comparison-type problems with unknown difference amounts. Social validity data collected from the participants’ mothers and classroom teachers showed that both groups had positive views on the use of the schema approach in the instruction of verbal mathematics problem-solving skills.