This research project explores the effects of differentiated learning and flexible grouping on students’ learning in high school mathematics. Specifically, the research demonstrates the effects of flexible grouping in a team-taught environment on students’ engagement and achievement. In this research study, students from two sections of team-taught Algebra 1 were used to determine changes in levels of engagement and achievement. First, students were grouped into a remediation group or an independent learning group based on their level of proficiency on an initial formative assessment. Students received instruction, practiced the necessary skills, and were assessed to conclude the study. Additionally, the researcher tracked the practice completion percentage for each group to determine if engagement levels were affected by the learning environment. Overall, flexible grouping strategies positively affected engagement levels and assessment scores for the low-ability learners in the remediation group. The engagement levels and assessment scores for students in the independent learning group were less significant than the results observed in the remediation group. Therefore, flexible grouping strategies play a significant role in teaching and learning for low-ability students. This research project aims to equip teachers with the knowledge and confidence to implement these strategies to provide authentic and engaging learning environments for all students.