A growing body of literature supports the effectiveness of Modified Schema-Based Instruction (MSBI) to improve mathematical problem-solving for students with autism spectrum disorder (ASD) and intellectual disability (ID). MSBI is an intervention package that teaches students to identify the problem structure and use a problem-solving heuristic to solve mathematical word problems. Previous research has primarily implemented MSBI in a one-on-one setting with a researcher as the interventionist. This study aimed to investigate the effects of a teacher-delivered MSBI in a small group format on the multiplicative word problem-solving skills of six middle school students with ASD/ID as well as their ability to generalize from word problems to video-based problems. Results of the multiple probe across participants design indicate a functional relation between MSBI and word problem-solving, but generalization varied across participants and maintenance was limited to two participants due to the coronavirus disease 2019 pandemic school closures. Implications for practice and future research are discussed.