#1 Largest Private Schools in Ontario, CA
Ontario Christian School
Christian school (nondenominational) · Grades Pre-K–12
1,438 students
Ontario, CA
B+Overall grade1,438 students17 students per teacher
2026 lists
Largest Private Schools in Ontario, CA
The private schools in Ontario, CA with the most students. Top 8 of 8 schools.
#2 Largest Private Schools in Ontario, CA
St. George Parish School
Parish school · Grades K–8
316 students
Ontario, CA
BOverall grade316 students22 students per teacher
#3 Largest Private Schools in Ontario, CA
Port View Preparatory
Special education school · Grades 1–12
163 students
Ontario, CA
B-Overall grade163 students10 students per teacher
#4 Largest Private Schools in Ontario, CA
Wesley College Preparatory School
Christian school (nondenominational) · Grades 9–12
150 students
Ontario, CA
BOverall grade150 students21 students per teacher
#5 Largest Private Schools in Ontario, CA
Orion International Academy
Independent school · Grades K–12
112 students
Ontario, CA
BOverall grade112 students10 students per teacher
#6 Largest Private Schools in Ontario, CA
Montecito Baptist School
Baptist school · Grades K–12
96 students
Ontario, CA
B+Overall grade96 students11 students per teacher
#7 Largest Private Schools in Ontario, CA
San Antonio Christian School
Seventh-day Adventist school · Grades K–8
60 students
Ontario, CA
B+Overall grade60 students15 students per teacher
#8 Largest Private Schools in Ontario, CA
The Good Shepherd Academy
Independent school · Grades 1–8
52 students
Ontario, CA
B+Overall grade52 students10 students per teacher
From official public records, updated October 2026.