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School Profile

Los Osos High School - Home of the Grizzlies
A California Distinguished and Gold Ribbon School

6001 Milliken Avenue, Rancho Cucamonga, CA 91737
Phone (909) 477-6900 Fax (909) 460-5872
Accredited by the Western Association of Schools and Colleges (WASC) through June 2025
2019-2020 School Profile    CEEB Code: 052987


Principal: Joshua Kirk
Assistant Principals: Cassandra Morton, Susan Malone, Larry Rook, Jim Woolery
Krystle Arzola A-Caz
Kelly Shaw Ce-Fl
Cynthia Deiner Fo-Jang
Victor Solis  Jann-Mas
Kevin Morris Mat-Q
Jim McDonald R-Sz
Richard Revard T-Z


Los Osos High School is one of eight comprehensive high schools within the Chaffey Joint Union High School District. The school is located in the suburban, predominantly middle-class community of Rancho Cucamonga. The majority of families live in single-family homes with many parents commuting to work out of the immediate area.

The physical plant consists of six buildings including a 1,250 seat theater and stadium with a seating capacity of 4,700. The school is designed to accommodate 2,600 students. At this time, Los Osos High School is serving 2972 students.

The student population breakdown of Los Osos is Hispanic (36%) with the second and third largest sub-group populations being White (34%) and Asian (17%). Those students eligible for free and reduced lunches make up 34% of the total school population while 63 students (2%) are currently classified as Limited English Proficient (English Learners).

All students study the state and district mandated core curriculum and follow the established graduation requirements.

The majority of funding comes from the district’s general fund. Categorical monies are utilized to assist English Learners.

Each class is 56 minutes except for period two when there is an additional six minutes for the announcements. Each Friday is a late start day when meetings, collaboration and staff in-services are scheduled. The only minimum days scheduled are the day after Back-To-School Night in August, and three at the end of each semester for school-wide final examinations.

In addition to the core and elective courses taken by our students, the school offers a full athletic program, as well as instrumental, vocal music, drama and dance.


English 4 years; Mathematics 2 years; Physical Science 1 year; Life Science 1 year; World History 1 year; US History 1 year; Physical Education 2 years; Government 1 semester; Economics 1 semester; Foreign Language or Fine Arts 1 year; Computer Studies 1 semester; Focus Area (taken from Fine Arts, Business Education, Home Economics, Industrial Technology, Foreign Language)
2 years; Electives 4 years (65 or 70 credits).


HONORS/Advanced Placement Courses
24 AP Courses in:

AP Biology, AP Calculus, AP Calculus BC, AP Chemistry, AP Chinese,  AP Computer Science, AP Computer Science Principals, AP Economics, AP English Literature, AP English Composition, AP French, AP U.S. Government,AP Human Geography, AP Latin, AP Physics, AP Psychology, AP Research, AP Seminar, AP Spanish Language, AP Spanish Literature, AP Statistics, AP Studio Art, AP U.S. History, AP World History.


7 Honors courses in: Int Math II, Int Math III, English I, English II, Pre-Calculus, Biology I, Pre AP Spanish III


Five credits are granted for completion of semester courses. 2.5 credits are granted for quarter courses. Students normally are enrolled in 6 classes each semester.

Rank is calculated at the end of every semester grading period using the grade point average of all marks earned in grades 9, 10, 11 and 12. Rank is weighted with extra points given in Honors and AP courses.


Grade Honors/AP
A = 4 5
B = 3 4
C = 2 3
D = 1  
F = 0  


Athletics – LOHS has a comprehensive athletics program that includes nineteen sports. It competes at the highest levels of athletics offered in California. In its short history, Los Osos has won 105 Baseline League championships. There have also been 25 CIF Championship appearances, 13 CIF Championship titles, 6 appearances in California State Playoffs, 1 Regional State Championship and 2 California State Championship Game appearances. Along with these accomplishments, Los Osos has state of the art facilities that include a 3200 square foot weight room, 4700 seat stadium, all-weather track, synthetic turf football field, an Olympic sized pool and a college level training room.

Publications – Los Osos High School’s journalism course seeks to develop well-rounded journalists and highly experienced editors who are trained to engage and question the world around them responsibly, reasonably, and creatively. The goal of the course is to prepare students with the skills necessary to pursue college level journalism, and it requires students to practice daily in order to meet the goal in an academic but enjoyable manner. The course, furthermore, is designed to publish an eight page monthly newspaper, The Grizzly Gazette. Newspaper articles cover a wide variety of topics from a student’s perspective. Well-informed and well-educated, Grizzly Gazette journalists provide the student body with accurate and reliable information, thereby serving our school campus and our surrounding community.

Band and Color Guard – The Los Osos Band, Orchestra & Color Guard Program has built a reputation as one of the finest musical organizations in Southern California. The concert bands and orchestra have consistently earned “Superior” ratings at music festivals throughout the state. The Jazz Band has appeared at the Reno Jazz Festival and has earned recognition at a variety of festivals and popular venues throughout the region. The Color Guard and Winter Guard have consistently been medalists in the championships sponsored by the Winter Guard Association of Southern California and The Los Osos Marching Regiment has twice appeared at the Fiesta Bowl National Band Tournament and the Fort McDowell Fiesta Bowl Parade in Phoenix, Arizona, and earned top music and marching awards at both of those events. The Marching Band has won the Las Vegas Invitational 3 times and has been a "Bands of America" regional finalist. The marching band has consistently been ranked in the top 12 of high school marching bands in Southern California for the past decade, according to the Southern California School Band and Orchestra Association and earned gold medals at marching band championships in 2007 and 2014.

Choir – The choirs at Los Osos High School have developed a reputation for excellence throughout Southern California over the past five years. In that time, the program has grown to include five curricular choirs and an extra-curricular a cappella and vocal jazz ensemble. All of the LOHS choirs consistently receive superior ratings at music performance and sight reading festivals through the Southern California Vocal association. In 2019, the LOHS Chamber Singers were asked to perform in the Lewis Family Playhouse’s Broadway at the Gardens production of The Hunchback of Notre Dame, while Serenata Treble Choir were invited to perform with the Inland Master Chorale in their performance of John Rutter’s Mass of the Children.

Library Media Center – The goal of Los Osos High School Library Media Center (LMC) is to ensure that students and staff are effective users of ideas and information and to inspire a love of reading. The library plan is to support the curriculum by providing appropriate print and non-print materials, to provide opportunities for students to use current technology, and to provide opportunities for students to read and study. Classes visit the LMC daily to utilize the computer labs and to take advantage of over 20,000 library and reference books. Students can also visit the library before school, during lunch, and after school. Free tutoring is available during those times.

SAT, ACT, API and AP Data



  # of students tested Critical Reading Math Writing
12-13 515 520 542 512
13-14 531 511 532 506
14-15 522 523 544 511
15-16 516 515 538 505
16-17 724 570 585 562
17-18 758 578 597 570
18-19 804 NA 592 575




  # of students tested English Reading Math Composite
12-13 183 23.0 23.7 24.6 23.6
13-14 198 22.5 23.6 23.9 23.2
14-15 180 22.7 23.5 24.5 23.5
15-16 219 22.9 23.9 24.4 23.7
16-17 219 23.7 24.1 25.6 24.4
17-18 215 24.7 24.8 25.1 24.6
18-19 204 24.2 24.4 25.0 24.4


Advanced Placement Exams

  Total # of Exams Total # of Students who Passed with 3 or Better Percentage Passed
13-14 1536 499 68%
14-15 1641 549 68%
15-16 1568 602 74%
16-17 1845 726 83%
17-18 2247 1679 75%
18-19 2442 1749 72%


Standards Met & Exceeded

  ELA Math
2014-2015 78% 55%
2015-2016 79% 55%
2016-2017 71% 53%
2017-2018 74% 53%
2018-2019 81% 58%