Castilleja School Admissions Consulting
Expert guidance for families applying to Palo Alto’s only nonsectarian all-girls day school, grades 6–12.
Cardinal Education is an independent educational consulting company. We are not affiliated, associated, authorized, endorsed by, or in any way officially connected with any private or public school, including Castilleja School.
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About the School
About Castilleja School
Castilleja School is an independent all-girls day school in Palo Alto serving grades 6 through 12. Founded in 1907 by Stanford graduate Mary Ishbel Lockey, it remains the only nonsectarian all-girls middle and high school in the San Francisco Bay Area. Its motto, Women Learning. Women Leading is not decoration. It describes how the school is built: interdisciplinary, deep-dive coursework grounded in research on how adolescent girls actually learn. About 416 students attend, 180 in the Middle School and 236 in the Upper School, with an average class size of 14 and a 7:1 student-teacher ratio. Seventy-five percent identify as students of color, and 90% of faculty hold advanced degrees.
Castilleja School Fast Facts
Location
1310 Bryant Street, Palo Alto, CA 94301
School Type
Independent, all-girls, day school
Grades Served
Middle School 6–8; Upper School 9–12
Total Enrollment
416 students
Middle School Enrollment
180 students
Upper School Enrollment
236 students
Average Class Size
14
Student-Teacher Ratio
7:1
Primary Entry Point
6th grade, with roughly 60 spaces available
Additional Entry Grades
7, 8, 9, 10, and 11
College Enrollment
97% of graduates enroll at four-year colleges
Gap Year
About 5% of graduates
Application Opens
September 1, 2026, on Ravenna
Application Deadline
January 5, 2027
Decisions Released
March 12, 2027, at 4:00 p.m. on Ravenna
Athletics
22 teams across 11 sports
Testing
ISEE, SSAT, and STAR scores are not considered
Transportation
Free morning and afternoon buses and shuttles
Academic Snapshot
Faculty with Advanced Degrees
90%
Median Unweighted GPA, Six Semesters
3.96
Median Weighted GPA, Six Semesters
4.14
AP Exams, May 2025
181 exams by 104 students, 79% scoring 4 or 5
Students Identifying as Students of Color
75%
Graduating Class Size, Class of 2026
51
Castilleja does not rank students and does not teach an AP curriculum. Its most rigorous courses are faculty-designed Advanced Topics courses, first offered in 2012. Nine departments organize the program: Computer Science and Engineering, English, History and Social Science, Mathematics, Science, Visual and Performing Arts, World Languages, and Fitness and Wellness. A three-person office handles college counseling.
The school is accredited by the Western Association of Schools and Colleges and belongs to One Schoolhouse, the International Coalition of Girls’ Schools, the National Association of Independent Schools, the National Association for College Admission Counseling, the Western Association for College Admission Counseling, and the Association of College Counselors in Independent Schools. It partners with and hosts the Peninsula Bridge Program each summer.
For a full walkthrough of the application, including what the admissions committee weighs most heavily at each entry point, see our complete Castilleja School admissions guide.
Castilleja Admissions Timeline and Events for 2026–27
Castilleja publishes firm dates for the application milestones and runs its Discover Castilleja event series each fall. Individual event times are released on Ravenna rather than the school website, so register early. Some events require a submitted preliminary application before you can sign up.
Application Opens on Ravenna
September 1, 2026 (For students entering in fall 2027)
Admission Information Sessions & Parent/Guardian Meetups
Fall 2026 (Zoom; meetups require a submitted preliminary application)
Middle School & High School Preview Events
November 9 and November 14, 2026 (In-person Preview Days)
Campus Visit & Student Interview
Fall 2026 into winter (Requires a submitted preliminary application; book early)
Preliminary Application Due
January 5, 2027 (Submit early to unlock event registration)
Full Application Due
January 5, 2027 (Transcripts accepted through the end of January)
Decision Letters Mailed
March 11, 2027
Decisions Posted on Ravenna
March 12, 2027, 4:00 p.m.
What Makes Castilleja’s Admissions Process Unique?
Castilleja evaluates applicants against five named values it calls the 5 Cs: conscience, courtesy, character, courage, and charity. That is unusually explicit. Most selective schools describe fit in vague terms, while Castilleja tells you the vocabulary its committee actually uses. Because no test score enters the file, everything else carries more weight. The interview, the timed writing sample, the questionnaires, and the recommendations become the whole picture. The committee reads several hundred applications for roughly 60 sixth-grade seats, so a merely strong application will not separate your daughter from the field.
Top Tips for Applying
- Submit the preliminary application early in fall 2026. Several Discover Castilleja events will not let you register until it is in.
- Learn the 5 Cs before the interview and be able to speak to them honestly, without reciting them.
- Treat the timed writing sample as a skills test, not a knowledge test. Practice organizing a response under thirty minutes.
- Ask for recommendations in mid-November, once teachers have had a full term to form a real impression.
- Apply to the entry point that fits, not the one that seems easiest. Sixth grade has the most seats by a wide margin.
Best Practices for Families
- Attend at least one Discover Castilleja event and register on Ravenna as soon as sign-ups open.
- Answer the parent questionnaire in your own voice. Committees notice when a parent statement reads like a résumé.
- Let your daughter answer her own interview questions. Coached answers are transparent and they cost more than they gain.
- Confirm every requirement on the school’s own admission pages before submitting, since details shift year to year.
- Plan transportation early if you live outside Palo Alto. Free shuttles serve several Peninsula pickup points.
What the Castilleja Application Requires
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01Preliminary Application
A short form that gates the rest of the process. It must be in before your daughter can register for a campus visit, an interview, or a parent meetup. Fee waivers are available on request.
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02Campus Visit and Student Interview
Required for every applicant. Middle School conversations run about 15 minutes after the campus visit. High School interviews run about 20 minutes on Zoom, with sign-ups emailed after January 5, 2027. Castilleja says there are no right answers, and means it, but a student who can point to something specific she noticed still lands better than one offering general enthusiasm.
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03Online Writing Sample
Every Middle and High School applicant types a timed online essay, built for fifteen to twenty minutes with thirty as the maximum. Register through Ravenna. The challenge is structural rather than intellectual. Most students generate ideas easily and struggle to shape them under a clock.
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04Student Questionnaires and Essays
Applicants describe what matters to them through questionnaires and essays. High School candidates add a Student Activities and Interest form. This is the only part of the file your daughter fully controls, and it is where a distinctive application separates from a merely accomplished one.
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05Parent Questionnaire
The committee is reading for how well you know your daughter, including where she still has room to grow. Candor reads better than polish.
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06Recommendation Letters
Requirements differ by division, and this trips up more families than any other step. Middle School applicants need a principal or counselor, a current homeroom or language arts teacher, and a previous-year homeroom or language arts teacher. High School applicants need a current principal or counselor, a current English teacher, and a current math teacher. Castilleja neither requires nor encourages supplemental letters from coaches, private instructors, or mentors. Interests outside the classroom belong in the questionnaire forms instead.
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07Transcripts
Covering 2025–26 and the first grading period of 2026–27, plus any prior standardized testing on record. Deliver the signed Transcript Release and Confidentiality Form to your daughter’s current school. Transcripts are accepted through the end of January, when fall grading runs late.
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08Testing
Castilleja does not require or consider the ISEE, SSAT, or STAR. Scores sent anyway are not added to the file. The practical consequence: no test result exists to offset a weaker transcript or a flat interview.
How Cardinal Education Helps
We have guided Bay Area families through the Castilleja process for nearly two decades, and our private school admissions consulting starts well before the application does. When no test score exists to speak for a student, the interview and the writing become everything, so that is where we invest: helping your daughter think clearly under time pressure, speak about herself without performing, and understand what conscience and courage actually look like in her own life. That work outlasts the admissions cycle. Asian American families navigating this process often have questions specific to their experience at Castilleja. If you need guidance, visit our dedicated page for Asian American admissions.
“Cardinal Education helped us navigate the Castilleja process with confidence and clarity. Our daughter is now thriving in 7th grade, and we could not be more grateful.”— Palo Alto Parent, Class of 2028
Frequently Asked Questions About Castilleja Admissions
Does Castilleja require the ISEE or SSAT?
What is Castilleja’s acceptance rate?
How big is the Asian American population at Castilleja?
Which grades does Castilleja admit?
Can students who do not live in Palo Alto attend?
Does Castilleja accept international students?
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