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Best Washington Private Schools Belonging to Membership Associations (2026)

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

Membership Association
# Schools
# Students
% Minority
AdvancED, Southern Association of Colleges and Schools, Council on Accreditation and School Improvement
2
199
15%
Accelerated Christian Education (ACE) or (School of Tomorrow)
10
881
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
44%
Association Montessori International (AMI)
7
360
16%
Association Montessori Internationale (AMI)
2
345
53%
Association of Christian Schools International (ACSI)
72
26,363
27%
Association of Christian Teachers and Schools (ACTS)
5
2,738
33%
Association of Classical and Christian Schools (ACCS)
11
3,441
13%
Association of LD Schools (ALDS)
1
426
29%
Association of Waldorf Schools of North America
8
1,162
14%
Children and Adults with Attention Deficit or Hyperactivity Disorder (CHADD)
1
90
35%
Christian Schools International (CSI)
14
4,869
15%
Cognia
35
11,303
39%
Council of Bilingual Education
2
129
-
Educational Records Bureau
1
306
70%
Evangelical Lutheran Education Association (ELEA)
8
625
33%
General Conference of the Seventh Day Adventist Church (GCSDAC)
22
1,624
33%
Institute for Independent Education
5
1,426
17%
International Baccalaureate (IB) World School
5
1,758
54%
International Boys Schools Coalition
1
902
68%
International Montessori Council (IMC)
1
26
50%
Jesuit Schools Network
1
115
99%
Jesuit Secondary Education Association (JSEA)
4
2,436
31%
Learning Disabilities Association of America (LDA)
5
222
27%
Middle States Association of Colleges and Secondary Schools
2
578
17%
Montessori Educational Programs International (MEPI)
1
28
26%
National Association for the Education of Young Children
39
2,234
38%
National Association of College Admissions Counselors
3
2,225
51%
National Association of Episcopal Schools (NAES)
1
49
30%
National Association of Independent Schools (NAIS)
58
18,088
37%
National Association of Laboratory Schools
1
29
-
National Association of Private Catholic and Independent Schools (NAPCIS)
2
184
54%
National Association of Private Special Education Centers
1
44
38%
National Catholic Education Association
1
375
47%
National Catholic Educational Association (NCEA)
81
23,163
30%
National Christian School Association (NCSA)
4
238
23%
National Coalition of Alternative Community Schools
1
50
30%
National Coalition of Girls
4
1,322
63%
National Council for Private School Accreditation
8
1,374
34%
National Honor Society (NHS)
2
5,109
50%
National Independent Private Schools Association
11
2,513
23%
National Junior Honor Society (NJHS)
1
4,952
51%
National Lutheran Schools Accreditation
6
1,194
20%
National Society of Hebrew Day Schools (NSHDS)
1
259
3%
Northwest Association of Accredited Schools
33
7,564
24%
Northwest Christian Schools International (NWCSI)
2
594
9%
Not Available (School did not report any membership associatons).
1
88
13%
NWAIS (Northwest Association of Independent Schools)
48
11,902
39%
Other associations(s) for exceptional children
2
212
34%
Other Montessori association(s)
40
2,679
37%
Other religious school association(s)
26
4,043
36%
Other school association(s)
81
18,434
25%
Other special emphasis association(s)
12
2,896
27%
Prizmah: Center for Jewish Day Schools
1
65
3%
Progressive Education Network
1
9
-
Society For Classical Learning
1
173
41%
Southern Baptist Association of Christian Schools (SBACS)
4
618
18%
State or regional independent school association
45
10,243
28%
The Association of Boarding Schools (TABS)
2
1,348
57%
Waldorf Early Childhood Association of North America
4
528
22%
Western Association of Schools and Colleges (WASC)
6
1,678
22%
Wisconsin Evangelical Lutheran Synod School Accreditation (WELSSA)
1
109
21%

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