This study aimed to determine whether or not Differentiated Instruction Model (DIM) had an effect on students' performance in mathematics. The two groups were preselected on the basis of their final rating in Mathematics I before randomly assigning the matched pairs to the two groups. One group was exposed to Differentiated Instruction Model and the other to the traditional method of teaching. Differentiated Instruction Model in this study modified the content of the lesson by adjusting the level of difficulty of the activities and assignment based on the pre-assessment results given before the start of every lesson. Students were grouped as basic and average learners on the basis of their scores in the pre-assessment test. This study used the pretest-posttest control group quasi-experimental design. Sources of the data were the 60-item researcher made performance test in mathematics and observation checklist. Although the data showed no significant difference in the mean gain scores in the pretest and posttest mean scores of both groups, evidence showed that Differentiated Instruction Model had a positive impact on students since they got a higher mean gain score in the pretest-posttest mean scores. This implies that differentiated instruction can bring about better performance in mathematics compared to the traditional approach. Moreover, the teacher-observers remarked that students in the DIM group were gratified and free from anxiety each time they worked on the activities and homework. They further observed that students were becoming independent learners.