Students who struggle with learning mathematics often have difficulties with geometry problem solving, which requires strong visual imagery skills. These difficulties have been correlated with deficiencies in visual working memory. Cognitive psychology has shown that chunking of visual items accommodates students’ working memory deficits. This study investigated the effects of visual-chunking representation as a testing accommodation for improving students’ geometry problem-solving performance. Participants were four third-graders with difficulties in mathematics. An adapted reversal design was employed to examine the students’ performance changes during standard testing conditions and accommodated testing conditions. During the accommodated condition, students were presented with visual-chunking images. Results suggested that the visual-chunking representation accommodation improved students’ performance on geometry problem-solving tasks, and an interview confirmed students’ preference for the visual-chunking representation approach.