Personal best goals (PB goals) articulate a target performance standard that matches or exceeds one's previous best. This study examined the role of PB goals in academic and social functioning. Alongside academic and social outcome measures, PB goal items were administered to 249 high-school students at the beginning and end of their school year. Longitudinal structural equation modeling suggested, at Time 1, PB goals significantly predicted students' deep learning, academic flow, academic buoyancy, positive teacher relationship, and favorable attitudes toward peer cooperation. Further, at Time 2, the effects of PB goals on deep learning, academic flow, and positive teacher relationship remained significant after controlling for prior variance of corresponding Time-1 factors, suggesting sustained benefits of PB goals in students' academic and social development. These findings hold substantive, applied, and methodological implications for researchers and practitioners seeking to examine and harness PB goals in educational settings. (Contains 3 tables and 2 figures.)