#1 Largest Private Schools in Oak Park, IL
Fenwick High School
Parish school · Grades 9–12
1,024 students
Oak Park, IL
A+Overall grade1,024 students12 students per teacher
2026 lists
Largest Private Schools in Oak Park, IL
The private schools in Oak Park, IL with the most students. Top 9 of 9 schools.
#2 Largest Private Schools in Oak Park, IL
Ascension Elementary School
Diocesan school · Grades Pre-K–8
322 students
Oak Park, IL
AOverall grade322 students12 students per teacher
#3 Largest Private Schools in Oak Park, IL
St. Giles School
Diocesan school · Grades Pre-K–8
264 students
Oak Park, IL
AOverall grade264 students12 students per teacher
#4 Largest Private Schools in Oak Park, IL
The Field School
Christian school (nondenominational) · Grades Pre-K–8
227 students
Oak Park, IL
BOverall grade227 students14 students per teacher
#5 Largest Private Schools in Oak Park, IL
St. Catherine Siena-St. Lucy School
Diocesan school · Grades Pre-K–8
175 students
Oak Park, IL
B-Overall grade175 students16 students per teacher
#6 Largest Private Schools in Oak Park, IL
The Childrens School of Oak Park
Alternative school · Grades K–8
132 students
Oak Park, IL
BOverall grade132 students11 students per teacher
#7 Largest Private Schools in Oak Park, IL
Alcuin Montessori School
Montessori school · Grades Pre-K–8
90 students
Oak Park, IL
A+Overall grade90 students3 students per teacher
#8 Largest Private Schools in Oak Park, IL
West Suburban Montessori School
Montessori school · Grades Pre-K–6
42 students
Oak Park, IL
B+Overall grade42 students8 students per teacher
#9 Largest Private Schools in Oak Park, IL
Cornerstone Academy
Christian school (nondenominational) · Grades 9–12
23 students
Oak Park, IL
AOverall grade23 students6 students per teacher
From official public records, updated October 2026.