Team-based learning (TBL) is an innovative form of collaborative learning. The purpose of this study was to evaluate TBL's effect on the performance and satisfaction of grade 7 students in biology in a private school in Lebanon, as well as teachers' willingness to implement this new methodology. An exploratory study was performed whereby two biology units were taught to two groups of students using either TBL (60 students) or traditional lecture-based instruction (30 students). Later, a summative test was administered to evaluate students' performance. Students' attitudes were evaluated using a questionnaire and teachers' classroom observations. Finally, science teachers' willingness to try TBL in their classes was assessed using a questionnaire (14 teachers). Results showed that underachievers taught according to TBL did better than underachievers taught with the lecture-based approach. The majority of students enjoyed TBL and found it useful and fun. Finally, science teachers agreed that TBL is a good alternative to the traditional lecture-based method.