Private schools, in some form, existed long before the concept of free public education in America. Students were often educated through church-sponsored programs, private tutoring, and boarding schools. Public schools on a large scale were proposed by Horace Mann in the 1830s. The concept gained momentum, and by 1870, nearly 80% of kids aged 5 to 14 were enrolled in public schools. Today, according to the most recent enrollment data, about 4.7 million students—or 10% of students enrolled in kindergarten through grade 12—are enrolled in private schools.

Private schools are widely marketed as a better option when compared to public schools, and private school proponents will often point to standardized test scores to substantiate this claim. While private school students have consistently outperformed public school students on standardized tests, recent studies have shown private schools themselves are not the primary driver of success, nor are standardized tests the most accurate measure of student well-being.

Researchers have found that student success is more directly related to family attributes, like having parents who graduated from college, and higher incomes—more common amongst private school students than public school students—than simply whether the students attended a public or private school.

Still, private schools provide unique advantages and opportunities like smaller class sizes, more individualized instruction, and greater curricular flexibility. To better understand how private school offerings vary across the country, Stacker compiled a list of the best private high schools in Illinois using 2023 rankings from Niche. Niche uses eight weighted factors for its rankings. A majority of the score is based on academics and grades, but other factors include culture and diversity, health and safety, clubs and activities, resources, and surveys of parents, teachers and students.

30. St. Viator High School

District: Arlington Heights- Enrollment: 875 (16:1 student to teacher ratio)- Niche grade: A+

29. Regina Dominican High School

District: Wilmette- Enrollment: 258 (9:1 student to teacher ratio)- Niche grade: A+

28. GCE Lab School

City: Chicago- Enrollment: 61 (6:1 student to teacher ratio)- Niche grade: A+

27. Ida Crown Jewish Academy

District: Skokie- Enrollment: 220 (6:1 student to teacher ratio)- Niche grade: A+

26. Naperville Christian Academy

District: Naperville- Enrollment: 128 (7:1 student to teacher ratio)- Niche grade: A+

25. Wolcott College Prep

City: Chicago- Enrollment: 150 (4:1 student to teacher ratio)- Niche grade: A+

24. St. Francis High School

District: Wheaton- Enrollment: 698 (13:1 student to teacher ratio)- Niche grade: A+

23. Benet Academy

District: Lisle- Enrollment: 1,357 (20:1 student to teacher ratio)- Niche grade: A+

22. GEMS World Academy Chicago

City: Chicago- Enrollment: 440 (5:1 student to teacher ratio)- Niche grade: A+

21. Keith Country Day School

City: Rockford- Enrollment: 286 (8:1 student to teacher ratio)- Niche grade: A+

20. Fenwick High School

District: Oak Park- Enrollment: 1,197 (14:1 student to teacher ratio)- Niche grade: A+

19. Loyola Academy

District: Wilmette- Enrollment: 2,000 (13:1 student to teacher ratio)- Niche grade: A+

18. The Einstein Academy

District: Elgin- Enrollment: 89 (5:1 student to teacher ratio)- Niche grade: A+

17. The Chicago Academy for the Arts

City: Chicago- Enrollment: 119 (2:1 student to teacher ratio)- Niche grade: A+

16. Christian Heritage Academy

District: Northfield- Enrollment: 421 (11:1 student to teacher ratio)- Niche grade: A+

15. Morgan Park Academy

City: Chicago- Enrollment: 490 (9:1 student to teacher ratio)- Niche grade: A+

14. Elgin Academy

District: Elgin- Enrollment: 227 (5:1 student to teacher ratio)- Niche grade: A+

13. Northridge Preparatory School

District: Niles- Enrollment: 330 (10:1 student to teacher ratio)- Niche grade: A+

12. Beacon Academy

District: Evanston- Enrollment: 213 (7:1 student to teacher ratio)- Niche grade: A+
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11. St. Ignatius College Prep

City: Chicago- Enrollment: 1,512 (16:1 student to teacher ratio)- Niche grade: A+

10. Rochelle Zell Jewish High School

District: Deerfield- Enrollment: 185 (6:1 student to teacher ratio)- Niche grade: A+

9. Lycée Français de Chicago

City: Chicago- Enrollment: 746 (7:1 student to teacher ratio)- Niche grade: A+

8. Woodlands Academy of the Sacred Heart

District: Lake Forest- Enrollment: 131 (6:1 student to teacher ratio)- Niche grade: A+

7. Francis W. Parker School

City: Chicago- Enrollment: 935 (9:1 student to teacher ratio)- Niche grade: A+
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6. Roycemore School

District: Evanston- Enrollment: 244 (6:1 student to teacher ratio)- Niche grade: A+

5. British International School of Chicago, South Loop

City: Chicago- Enrollment: 651 (9:1 student to teacher ratio)- Niche grade: A+

4. North Shore Country Day

District: Winnetka- Enrollment: 547 (7:1 student to teacher ratio)- Niche grade: A+

3. Latin School of Chicago

City: Chicago- Enrollment: 1,155 (8:1 student to teacher ratio)- Niche grade: A+

2. Lake Forest Academy

District: Lake Forest- Enrollment: 436 (6:1 student to teacher ratio)- Niche grade: A+

1. University of Chicago Laboratory Schools

City: Chicago- Enrollment: 2,051 (8:1 student to teacher ratio)- Niche grade: A+