Justin-Siena is a Catholic high school in the Lasallian tradition called to provide educational excellence in a loving, Christ-centered community that prepares students to serve and to lead in an ever-changing world.
Faculty and staff strive to serve a diverse ethnic and socio-economic cross-section of the surrounding communities.
We provide a superior academic experience. We prepare our students to be well-rounded and well prepared for college & life. At the heart of the rigorous, college preparatory academic experience at Justin-Siena is our commitment to fostering a personal, caring, and challenging atmosphere.
When a challenging curriculum is paired with enriching activities outside the classroom, students are able to further discover their talents within. These opportunities provide students with an environment geared toward testing their limits and discovering their potential.
As Lasallians we are called to provide a human and Christian education. We are proud to have served local and international students in our inclusive and faith based community for over 50 years.
Quick Facts (2025-26)
- Top Ranked CA School
- Grades: 9-12
- Enrollment: 660 students
- Yearly Tuition: $24,500
- Average class size: 24 students
- Application Deadline: Dec. 20 / rolling
- Source: Verified school update
Top Rankings
Justin-Siena High School ranks among the top 20% of private schools in California for:
Category
Attribute
Student Body
AP Courses
Sports offered
School Overview
Religious Affiliation
Grades Offered
Grades 9-12
ADD/ADHD Support
Yes
Year Founded
1966
Colors
Blue, Red, Navy Blue
Summer School Offered
Yes
School Calendar
Last Day of School
Mon. May 25, 2026
Campus Size
37 acres
Student Body
Total Students
660 students
Student Body Type
Co-ed
% Students of Color
40%
State avg.: 51%
Students by Grade

Academics and Faculty
Total Classroom Teachers
58 teachers
Student-Teacher Ratio
11:1
National avg.: 13:1
% Faculty w/Advanced Degree
43%
Average Class Size
24 students
Number of AP Courses
40 courses
List of Courses Offered
Advanced Courses
Advanced DanceAdvanced Instrumental Music
Advanced Studio ArtAdvanced Theatre
AP Art HistoryAP Biology
AP Calculus ABAP Calculus BC
AP ChemistryAP Computer Science
AP EconomicsAP English Language Literature
AP Environmental ScienceAP Government
AP LanguageAP Micoeconomics
AP PhysicsAP Spanish
AP Studio ArtAP United States History
AP World HistoryHonors Civil Engineering
Honors English 11Honors English 12
Honors English 9Honors Introduction to Engineering
Honors PhysicsHonors Principles of Engineering
Honors Spanish IIHonors Spanish III
Honors TheatreHonors US History
Pre AP English Language and LiteratureTheatre in Production
Average SAT score
1170
(Out of 1600)
Average ACT score
28
(Out of 36)
Matriculation DataMatric. Data
Classroom Dress Code
Formal
Uniform polo shirt, uniform skirt and shorts, jeans, khaki colored pants
Tuition and Acceptance Rate
Admission Deadline
Dec. 20 / rolling
Yearly Tuition Cost
$24,500
Tuition Notes
The tuition packages is inclusive of most significant fees that Justin-Siena has typically charged families throughout the year. The following fees will no longer be assessed: student life, athletics, theatre, retreats, yearbook, or graduation.
% on Financial Aid
45%
Average Financial Aid Grant
$12,250
Admissions Director
Alicia Valdivia
Admissions Associate
Jeremy Tayson
Application URL
Sports
Total Sports Offered
16 sports
Extracurriculars
Total ExtracurricularsTotal Extra-curric.
11 extracurriculars
ExtracurricularsExtra-curric.
Club or Organization:
Culinary ClubFriday Night Live
LeadershipLiterary Magazine
Medical FuturesMock Trial
Multicultural ClubOutdoor Club
Robotics TeamStudent Ambassadors
Women's Empowerment
School Notes
- School Motto: Sempre Avanti
- Justin-Siena is a Catholic high school in the Lasallian tradition called to provide educational excellence in a loving, Christ-centered community that prepares students to serve and to lead in an ever-changing world.
- Sample of notable school alumni/alumnae:
- Josh Jackson - #4 NBA draft pick to Phoenix Suns
- Brett Wallace - Professional MLB player
- Olivia O'Brien - Singer, songwriter, Billboard Top 10
- Mark Rappaport - Special make-up effects artist, CEO and owner of Creature Effects Inc, a company that provided special effects for many famous films, including Seabiscuit, The Revenant, Cowboys and Aliens, 300, and The Last Samurai. He received a prestigious technical ac
Source: Verified school update
Frequently Asked Questions
How much does Justin-Siena High School cost?
Justin-Siena High School's tuition is approximately $24,500 for private students.
Who are famous alumni from Justin-Siena High School?
Justin-Siena High School famous alumni include: Josh Jackson, Brett Wallace, Olivia O'Brien and Mark Rappaport.
What sports does Justin-Siena High School offer?
Justin-Siena High School offers 16 interscholastic sports: Baseball, Basketball, Cheering, Cross Country, Dance, Football, Golf, Lacrosse, Soccer, Softball, Swimming, Tennis, Track and Field, Volleyball, Water Polo and Wrestling. Justin-Siena High School is ranked as one of the top 20% of private schools in California for most sports offered.
What is Justin-Siena High School's ranking?
Justin-Siena High School ranks among the top 20% of private schools in California for: Largest student body, Most AP courses offered and Most sports offered.
When is the application deadline for Justin-Siena High School?
The application deadline for Justin-Siena High School is Dec. 20 / rolling (applications are due on Dec. 20 but additional applications are reviewed year-round as space permits ).
School Reviews
5 9/1/2016
I am from Shanghai China. My husband and I are both baptised, we believe in God. We want to send our son Kevin to your school. Does Justin-Siena High School is a boarding school?
Endorse Justin-Siena High School. Endorsements should be a few sentences in length. Please include any comments on:
- Quality of academic programs, teachers, and facilities
- Availability of music, art, sports and other extracurricular activities
- Academic or athletic awards
Recent Articles

Transferring from Public to Private School Mid-Year: What to Expect
Considering a mid-year transfer from public to private school? Learn what to expect with admissions, academic placement, social adjustment, and financial aid to ensure a smooth transition.

A Guide to Day vs. Boarding School: Which Is Right for Your Family
Discover the key differences between day and boarding schools to determine the best fit for your child. Explore benefits, costs, lifestyle factors, and questions to help guide your family’s decision.

The A to Z of Private Schools 2025
Explore the A to Z of private schools in 2025—from admissions to tuition—offering parents and educators clear insights into today’s options.