Illinois Schools
- Ohio High School
- Okawville High School
- Old Town School Of Folk Music
- Old University Of Chicago
- Olivet Nazarene University
- Olive–harvey College
- Olney Central College
- Olympia Community Unit School District 16
- Olympia High School
- Orangeville High School
- Orion Community Unit School District 223
- Orion High School
- Orr High School
- Oswego Community Unit School District 308
- Oswego East High School
- Oswego High School
- Ottawa Township High School
- Our Lady Of Tepeyac High School
- Palatine High School
- Palos Heights School District 128
- Palos School District 118
- Paris Community Unit School District No 4
- Paris Cooperative High School
- Paris Union School District 95
- Park Forest Chicago Heights School District 163
- Park Ridge Youth Campus
- Park Ridge Niles School District 64
- Parkland College
- Parrish Elementary School
- Paul Robeson High School
- Paw Paw High School
- Paxton First Schoolhouse
- Paxton Buckley Loda Community Unit School District 10
- Paxton Buckley Loda High School
- Payson Community Unit School District 1
- Payson Seymour High School
- Pecatonica High School
- Pekin Community High School District 303
- Peoria Academy
- Peoria Heights Community Unit School District 325
- Peoria Heights High School
- Peoria High School
- Peoria Notre Dame High School
- Peoria Public Schools
- Peotone High School
- Perspectives Charter School
- Perspectives Charter Schools
- Peru Elementary School District 124
- Philip Rogers Elementary School
- Phoebe A Hearst Fine Arts Magnet School
- Pinckneyville Community High School
- Pittsfield High School
- Piven Theatre Workshop
- Plainfield Central High School
- Plainfield Community Consolidated School District 202
- Plainfield East High School
- Plainfield North High School
- Plainfield South High School
- Plano High School
- Pleasant Hill High School
- Pleasant Plains High School
- Polo Community High School
- Pontiac Community Consolidated School District 429
- Pontiac Township High School
- Pontiac William Holliday School District 105
- Posen Robbins School District 143½
- Prairie Central High School
- Prairie Ridge High School
- Prairie State College
- Prairieview Elementary School
- Princeton High School
- Princeville High School
- Principia College
- Pritzker College Prep
- Pritzker School
- Pritzker School Of Medicine
- Prophetstown High School
- Prospect Heights School District 23
- Prospect High School
- Prosser Career Academy
- Providence Catholic High School
- Providence St Mel School
- Proviso East High School
- Proviso Mathematics And Science Academy
- Proviso Township High Schools District 209
- Proviso West High School
- Putnam County High School
- Queen Bee School District 16
- Queen Of Peace High School
- Quest Academy
- Quigley South
- Quincy Notre Dame High School
- Quincy Public School District 172
- Quincy Senior High School
- Quincy University
- Rowva High School
- Rauner College Prep
- Reavis High School
- Red Hill Community Unit School District 10
- Reed Custer High School