Private School Review - Established 2003
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Washington Private Schools Belonging to Membership Associations

For the 2026-27 school year, there are 490 private schools belonging to membership associations in Washington.
The most popular school membership associations are National Catholic Educational Association (NCEA) (17% of schools), Other school association(s) (17% of schools) and Association of Christian Schools International (ACSI) (15% of schools).

Quick Facts (26-27)

  • # Private Schools: 490

Quick Facts (26-27)

  • # Private Schools: 490

Top Ranked Washington Private Schools by Membership Association (2026-27)

Membership Association
# Schools
# Students
% Minority
Accelerated Christian Education (School of Tomorrow) (ACE)
10
884
14%
Accreditation International
1
134
9%
Alternative School Network
1
111
22%
American Association of Christian Schools (AACS)
6
508
18%
American Montessori Society (AMS)
36
4,037
45%
Association for Middle Level Education (formerly NMSA) (AMLE)
1
826
47%
Association Montessori Internationale (AMI)
9
705
35%
Association of Christian Schools International (ACSI)
72
25,069
26%
Association of Christian Teachers and Schools (ACTS)
5
2,738
33%
Association of Classical Christian Schools (ACCS)
11
3,441
13%
Association of LD Schools (ALDS)
1
426
29%
Association of Waldorf Schools of North America (AWSNA)
8
1,159
14%
Children and Adults with Attention Deficit or Hyperactivity Disorder (CHADD)
1
90
35%
Christian Schools International (CSI)
14
4,795
15%
Cognia (formerly AdvancED / SACS CASI / NCA CASI) (Cognia)
62
16,651
32%
Council of Bilingual Education (PVSR legacy category)
2
129
-
Evangelical Lutheran Education Association (ELEA)
8
625
33%
General Conference of Seventh-day Adventists (Education) (GCSDAC)
21
1,624
33%
Institute for Independent Education (PVSR legacy category)
5
1,426
17%
International Baccalaureate World School (IB)
5
1,761
48%
International Boys' Schools Coalition (IBSC)
1
902
68%
International Coalition of Girls' Schools (formerly NCGS) (ICGS)
4
1,317
63%
International Montessori Council (IMC)
1
26
50%
Jesuit Schools Network (formerly JSEA) (JSN)
5
2,551
34%
Learning Disabilities Association of America (LDA)
5
222
27%
Middle States Association Commissions on Elementary and Secondary Schools (MSA-CESS)
2
438
19%
Montessori Educational Programs International (MEPI)
1
28
26%
National Association for the Education of Young Children (NAEYC)
39
2,235
38%
National Association of Episcopal Schools (NAES)
1
49
30%
National Association of Independent Schools (NAIS)
59
18,223
39%
National Association of Laboratory Schools (NALS)
1
29
-
National Association of Private Catholic and Independent Schools (NAPCIS)
2
184
54%
National Association of Private Special Education Centers (NAPSEC)
1
44
38%
National Catholic Educational Association (NCEA)
82
23,505
31%
National Christian School Association (NCSA)
4
238
23%
National Coalition of Alternative Community Schools (NCACS)
1
50
30%
National Council for Private School Accreditation (NCPSA)
8
1,233
37%
National Independent Private School Association (NIPSA)
11
2,483
18%
National Lutheran Schools Accreditation (NLSA)
6
1,212
23%
National Society of Hebrew Day Schools (NSHDS)
1
259
3%
Northwest Association of Independent Schools (NWAIS)
49
11,920
41%
Northwest Christian Schools International (NWCSI)
2
594
9%
Not Available (School did not report any membership associatons).
1
88
13%
Other associations(s) for exceptional children
2
212
34%
Other Montessori association(s)
39
2,563
35%
Other religious school association(s)
26
4,047
37%
Other school association(s)
81
18,490
25%
Other special emphasis association(s)
12
2,909
27%
Prizmah: Center for Jewish Day Schools (absorbed SSDSA) (Prizmah)
1
65
3%
Society for Classical Learning (SCL)
1
173
41%
Southern Association of Colleges and Schools Commission on Colleges (SACSCOC)
2
199
15%
Southern Baptist Association of Christian Schools (SBACS)
4
618
18%
State or regional independent school association
44
10,048
28%
The Association of Boarding Schools (TABS)
2
1,348
57%
Waldorf Early Childhood Association of North America (WECAN)
4
525
22%
Western Association of Schools and Colleges (Accrediting Commission for Schools) (ACS WASC)
6
1,646
37%
Wisconsin Evangelical Lutheran Synod School Accreditation (WELSSA)
1
109
21%

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