2020-2021 ICNS Member Schools
| AAA Academy | Blue Island |
| Agape Christian High School | Marion |
| All Saints Academy | Breese |
| Altamont Lutheran Interparish School | Altamont |
| Altus Academy | Chicago |
| American School | Lansing |
| Aqsa School | Bridgeview |
| Arie Crown Hebrew Day School | Skokie |
| Aurora Central Catholic High School | Aurora |
| Bais Yaakov High School of Chicago | Chicago |
| Bethal Lutheran School | Morton |
| Bethany Lutheran | Naperville |
| Brickton Montessori School | Chicago |
| Calvary Academy | Springfield |
| Calvary Academy | South Holland |
| Calvin Christian School | South Holland |
| Calvary Christian School | Naperville |
| Carriers of Light | Wheaton |
| Chiaravalle Montessori | Evanston |
| Chicago Academy for the Arts | Chicago |
| Chicago West Side Christian School | Chicago |
| Christ Lutheran High School | Buckley |
| Christ the King | Springfield |
| Christian Heritage Academy | Northfield |
| Concordia Place | Chicago |
| Cornerstone Christian Academy | Bloomington |
| Cornerstone Christian School | Chicago Heights |
| Countryside Day School | Northbrook |
| Daystar Academy | Chicago |
| Elgin Academy | Elgin |
| First Baptist Academy | O'Fallon |
| Francis W. Parker | Chicago |
| Good Shepherd Lutheran School | Collinsville |
| Good Shepherd Lutheran School | Pekin |
| Governor French Academy | Belleville |
| Grace Lutheran School | River Forest |
| Hanna Sacks Bais Yaakov | Chicago |
| Holy Family School | Chicago |
| ICCD Academy | Des Plaines |
| Ida Crown Jewish Academy | Skokie |
| Immanuel Christian Academy | Hillside |
| Immanuel Lutheran School | Palatine |
| Islamic Foundation School | Villa Park |
| Joan Dachs Bais Yaakov | Chicago |
| Joliet Catholic Academy | Joliet |
| Lake Forest Country Day School | Lake Forest |
| Lansing Christian School | Lansing |
| Lycee Francais de Chicago | Chicago |
| MCC Academy | Morton Grove |
| Marmion Academy | Aurora |
| Montessori Foundations of Chicago | Chicago |
| Montessori School of Lemont | Lemont |
| Near North Montessori | Chicago |
| North Park Elementary School | Chicago |
| North Shore Country Day School | Winnetka |
| Our Lady of Mt. Carmel Catholic School | Herrin |
| Our Savior's Lutheran | Springfield |
| Rogers Park Montessori | Chicago |
| Ronald Knox Montessori School | Wilmette |
| Sacred Heart Schools | Chicago |
| Science & Arts Academy | Des Plaines |
| Scuola Italiana Enrico Fermi | Chicago |
| Seton Montessori | Clarendon Hills |
| Solomon Schechter Day School | Northbrook |
| Southwest Chicago Christian | Palos Heights |
| Springfield Christian School | Springfield |
| St. Andrews | Park Ridge |
| St. Christopher School | Midlothian |
| St. Dennis | Lockport |
| St. Edward Catholic | Elgin |
| St. Francis High School | Wheaton |
| St. Isidore School | Bloomingdale |
| St. John's Lutheran | Country Club Hills |
| St. John's Lutheran | Bloomington |
| St. Luke's Academy | Montgomery |
| St. Patrick School | Washington |
| St. Paul's Lutheran School | Bourbonnais |
| St. Raymond School | Joliet |
| The Ancona School | Chicago |
| Timothy Christian School | Elmhurst |
| Trinity Lutheran | Stewardson |
| Trinity Oaks Christian Academy | Cary |
| Universal School | Bridgeview |
| Visitation School | Elmhurst |
| Wheaton Christian Grammar School | Winfield |
| Woodlands Academy | Lake Forest |
| Zion Lutheran School | Marengo |
| Zion Lutheran School | Mt. Pulaski |