Oak Brook
- County:
- DuPage County
- County Seat:
- No
- Area (mi²):
- 7.976
- State:
- Illinois
Oak Brook is a village located in DuPage County, Illinois. Oak Brook has a 2026 population of 8,188. Oak Brook is currently growing at a rate of 1.04% annually and its population has increased by 0.49% since the most recent census, which recorded a population of 8,148 in 2020.