This study examines the distribution, change, and impact of the Index of Teacher Academic Capital (ITAC) in all Illinois public schools from 2001 to 2006. The ITAC is a school-level composite of five measures: teacher ACT Composite and English scores, teacher Basic Skills Test results, teacher certification status, and teacher undergraduate college competitiveness. We find that students in high-poverty and high-minority schools, especially those in Chicago, had less access to high ITAC than their counterparts elsewhere. However, high-poverty schools statewide and high-minority schools in Chicago also experienced the greatest gains in ITAC over the time period. We show the impact of ITAC by using fixed-effects models, which reveal that schools that increase their ITACs also tend to improve their achievement. (Contains 7 endnotes, 13 figures and 16 tables.)