Centreville Layton School Photo - Beautiful campus

Best Delaware Private High Schools Belonging to National Association of Independent Schools (NAIS) (2025-26)

For the 2025-26 school year, there are 8 private high schools belonging to National Association of Independent Schools (NAIS) serving 4,374 students in Delaware. You can also find more schools membership associations in Delaware.
The top ranked private high schools belonging to National Association of Independent Schools (NAIS) in Delaware include Wilmington Friends School, Archmere Academy, and Sanford School.
The average acceptance rate is 76%, which is lower than the Delaware private high school average acceptance rate of 87%.
50% of private high schools belonging to National Association of Independent Schools (NAIS) in Delaware are religiously affiliated (most commonly Catholic and Friends).

Top Ranked Private High Schools Belonging to National Association of Independent Schools (NAIS) in Delaware (2025-26)

School
Location
Quick Facts
Centreville Layton School
Centreville Layton School Photo - Beautiful campus
Alternative School
6201 Kennett Pike
Wilmington, DE 19807
(302) 571-0230
Gr: K-12 | 97 students Avg. class size: 8 students Sports: 6 Tuition & acceptance rate listed
Wilmington Friends School
Wilmington Friends School Photo - Quaker education teaches students that they share in the obligation to answer what is best in themselves and in others--developing talents to the fullest, and respecting the strengths, efforts, and perspectives of all.
(Friends)
(1)
101 School Road
Wilmington, DE 19803
(302) 576-2900
Gr: NS-12 | 707 students Avg. class size: 12 students Sports: 14 | Extracurrculars: 39 Tuition listed
Archmere Academy
Archmere Academy Photo
(Catholic)
(7)
3600 Philadelphia Pike
Claymont, DE 19703
(302) 798-6632
Gr: 9-12 | 501 students Avg. class size: 15 students Sports: 20 | Extracurrculars: 38 Tuition listed
St. Andrew's School
(Episcopal)
350 Noxontown Rd
Middletown, DE 19709
(302) 285-4231
Gr: 9-12 | 315 students Sports: 15 Tuition listed
Saint Mark's High School
Saint Mark's High School Photo
(Catholic)
(10)
2501 Pike Creek Road
Wilmington, DE 19808
(302) 757-8721
Gr: 9-12 | 716 students Avg. class size: 20 students Sports: 17 | Extracurrculars: 34 Tuition listed
Sanford School
Sanford School Photo
(2)
6900 Lancaster Pike
Hockessin, DE 19707
(302) 235-6503
Gr: NS-12 | 703 students Avg. class size: 13 students Sports: 16 Tuition listed
The Tatnall School
The Tatnall School Photo - Tatnall's 110-acre campus is located just west of Wilmington in Greenville, Delaware. Housing a National Wildlife Federation-accredited schoolyard habitat, five outdoor classrooms and bordering the Downs Nature Conservancy, the spacious campus provides expansive playing fields and opportunities for outdoor environmental study.
(13)
1501 Barley Mill Road
Wilmington, DE 19807
(302) 892-4296
Gr: NS-12 | 486 students Avg. class size: 12 students Sports: 15 | Extracurrculars: 9 Tuition listed
Tower Hill School
Tower Hill School Photo - Tower Hill School resides on a 44-acre campus with state-of- the-art athletic facilities and impressive academic and arts areas.
2813 W 17th Street
Wilmington, DE 19806
(302) 575-0550
Gr: NS-12 | 849 students Avg. class size: 15 students Sports: 17 | Extracurrculars: 24 Tuition & acceptance rate listed

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