One challenge facing the fields of mathematics education and special education is how to design instruction on fraction concepts that can meet the needs of diverse learners. An innovation that shows promise is to base instructional design upon well-established trajectories of students’ fraction learning. However, little research has been done to establish the effectiveness of this approach. We report the results of the second of two small studies of an intervention developed using a validated trajectory of students’ fraction concepts. Mixed methods analyses were conducted on students’ problem-solving actions across instructional sessions as well as their performance on a standards-aligned measure of fractional knowledge before and after instruction. Results suggest increases in both conceptual understanding and performance for nine students. We discuss the findings in relation to practice from the fields of mathematics education and special education and point to areas for future research.