The Outdoor Advertising Association of Illinois (OAAI) is not-for-profit trade association representing outdoor advertising companies who conduct business in the state of Illinois. OAAI was established in 1895 to protect the interests, rights, and privileges of the outdoor advertising medium as they may be affected by legislative, administrative or judicial action.

OAAI is governed by a ten member board and administered by a full-time staff whose office is headquartered in Springfield, Illinois.