This study describes a science professional development (PD) project within a small Appalachian school district involving all elementary and middle school science teachers. Teachers receiving PD demonstrated statistically significant gains in content knowledge from pre- to post-testing, with higher post-test scores compared with science teachers from a district who did not receive PD. Students of teachers who received PD generally demonstrated greater gains in content knowledge from pre- to post-testing when compared with students of science teachers from a district who did not receive PD. Economically disadvantaged students of science teachers who received PD demonstrated increases in content knowledge from pre- to post-testing, with greater gains in comparison with economically disadvantaged students of science teachers who did not receive PD. This mixed methods research study contributes to the limited knowledge base for science education research in rural schools.