The importance of mathematical problem solving (MPS) has been widely recognized. While there has been significant progress in developing and studying interventions to support teaching and learning MPS for students with disabilities, the research on how to accurately and effectively assess the impact of those interventions has lagged, leaving a gap in understanding whether interventions are truly achieving their intended outcomes. The purpose of this mixed-method study was to explore how a dynamic assessment (DA) approach can be used in the context of an evidence-based MPS intervention, Enhanced Anchored Instruction, as an alternative means of assessing the MPS of students with disabilities. Our findings suggest that DA is an adequate assessment tool and can provide additional information for teachers to better understand the MPS strengths and challenges of students with disabilities such as MPS ownership transition. Study limitations, considerations for future research, and implications for practice are discussed, emphasizing the importance of rigorous evaluation of the DA approach to improve teaching and learning MPS for students with disabilities.