Even though school administrators and their leadership practices are rarely explored within science education research, our recent efforts to understand organizational influences on achievement disparities induced an elevated regard for elementary school principals. In this paper, we report on policy buffering by principals at schools whose science test scores exceed statistical expectations. We approached principals to learn more about their science program and the potential leadership and organizational infrastructures that might explain their schools' exemplary performance with students from diverse backgrounds. As street-level bureaucrats, principals are expected to translate formal policy while also ensuring the school is supportive of the teachers and the students. By applying a structure/agency perspective, principals were found to engage in the cognitive professional practice of buffering in four ways: adjusting school structures to accommodate new policies; negotiating compromises with central office about policy implementation; shielding teachers from low-priority policies; and occasionally encouraging teachers to preemptively engage in district-level representation to shape policy implementation. In addition, we uncovered many instances where principals were unwilling to deflect policy and worked with teachers accordingly. We learned that buffering is a cognitive act in which principals make rationale choices about policy and in certain instances will shield their school out of compassion for the teachers and students. It is likely that principal buffering contributes to the equitability and excellence of student performance on their schools' statewide science test.