Math skills vary greatly among students enrolled in introductory chemistry courses. Students with weak math skills (algebra and below) tend to perform poorly in introductory chemistry courses, which is correlated with increased attrition rates. Previous research has shown that retention of main ideas in a peer learning environment is greater when partners have dissimilar abilities. Therefore, in an effort to improve student learning outcomes, we implemented peer learning interventions in our introductory chemistry laboratories to determine if math skills were enhanced when partners differed in math ability. Student performance and attitudes were analyzed in laboratory sections consisting of instructor-assigned partners who differed in math ability, compared to sections where students self-selected a partner. Students who were assigned math partners of different ability showed an 8% improvement in chemistry math concepts compared to no improvement among those who self-selected a partner, as assessed using pre- and post-math tests. Mathematical learning gains were particularly large (16%) for those students in the 50th percentile of math performance. Students also reported a significantly more positive attitude change about working with others compared to students who self-selected a partner. In addition, assigned students demonstrated a more positive shift in self-concepts such as chemistry knowledge and laboratory skills. This study illustrates that peer learning can serve as a useful and easy-to-implement tool to strengthen math skills and improve student attitudes in introductory chemistry laboratories.