Summer Data Confirmation Window Now Open!

Now is the time to login to your Aeries Parent Portal to complete your summer data confirmation/summer registration.

Don't show again [x]

Los Osos High School Home

About Us

The Chaffey Joint Union High School District serves the communities of Ontario, Montclair, Rancho Cucamonga, and portions of Fontana, Upland, Chino, and Mount Baldy. With over 25,000 students, the District is the fourth largest high school district in California. It has eight comprehensive high schools, a continuation high school, an online high school, a community day school, an adult school, and alternative programs. The District offers a wide variety of instructional options that provide a quality education for each student, every day. The District's well-prepared, dedicated, and highly qualified teachers and support personnel are second to none.
The Chaffey Joint Union High School District Board of Trustees are steadfast in the belief that "Nothing is more important than student learning and their achievement."
Our daily purpose encompasses our commitment:
"To provide student learning, and ultimately their achievement, of the prescribed curriculum that takes place in the classroom under the direction of the teacher." The Chaffey District supports this daily act. We realize that our efforts uniquely influence the future of our community and of this nation, and we are passionate about doing whatever it takes to prepare students to be successful and contributing citizens of the 21st century.
The Chaffey District has provided a quality education for high school students in the area since 1911. As the District continues to grow and progress, we are poised to meet the challenge of providing the finest quality education possible for every student. 
About Us Image
All CJUHSD students will graduate ready for college and careers.

Recent News

WeTip - Be the solution


Be the Solution. If you have information regarding crime or misconduct at your school, call WeTip anonymously.

The Chaffey District Cares

The Chaffey District cares about your mental well-being. We partner with community agencies and mental health professionals to provide support to our students and staff. If you, or someone you know, is in crisis please contact the Community Crisis Response Team (909) 421-9233 - Click 'Read Full Story' for more information.

Upcoming Events

School Facts

  • 78% of Los Osos High School graduates meet the University of California and California State University A-G admissions requirements, making it a leader in San Bernardino County.
  • 98% of freshmen at Los Osos High School complete their first year of high school on track to graduate.
  • The CJUHSD has been named a Top Workplace by the Press-Enterprise and Inland News Group.
  • 2500 Advanced Placement exams are administered to students at Los Osos High School annually.

Principal's Message

Mr. Cypher
Dear Los Osos High School Students, Parents, and Guardians,  
I hope that you have had a chance to spend some quality time together with family and friends through these summer months. We have continued with a very robust summer school and continue to make history with the Chaffey District offering for the first time ever three sessions for summer learning. Many of our Grizzlies have remediated their grades from the past two school years during this summer school; I am very proud of these Grizzlies as they continue to get themselves back on track for Graduation and/or A-G completion.  Our goal is to get every Grizzly affected academically by the pandemic back on track and we will continue to offer remediation classes throughout the 2022-2023 school year. If you have questions about these opportunities, you may speak with a counselor or an assistant principal for more details.   
The first day of the 2022-2023 school year will be Wednesday, August 10th. We look forward to fully welcoming students back and we will continue with in-person instruction this fall. The District remains committed to ensuring the safety of our students and staff and will continue to monitor and adapt to health regulations from the state as well as the county. In-person instruction has proven to serve our students best, but we will provide alternatives to in-person instruction for those students who may need to remain in a virtual learning setting.  If you desire to discuss an alternative educational program for your student, please contact the school at 909-477-6900 this summer.   
All schools in the Chaffey Joint Union High School District will continue with the start time of 8:30 a.m. and concluding at 3:20 p.m. Friday hours will continue to be from 9:30 a.m. - 3:20 p.m. These start times are part of the legally-mandated late start for California high schools in 2022. Our bell schedule is attached and features a traditional 6-period day, with expanded 0 and 7-period opportunities for students who need additional access to academic courses.  
To our Seniors, the Class of 2023, your year is here!  The past three years have been a roller coaster the likes of which the world has never seen, yet you have made it this far and your year is finally here! Take a quick moment and savior it, and then realize that Hard Work Pays Off and your legacy is still ahead of you! So continue to Work Hard, Inspire Others, Lead with Integrity and Dream Big! And finally, welcome to the class of 2027! We look forward to welcoming you to Grizzlyland and the seeing the mark and impact you will make on Los Osos.  
Students: please remember to bring any textbooks you have so you can return them to the library on your designated registration day and time as indicated below:
Students/families will report for schedule pick-up/orientation based on last name according to the schedule below:
Monday, July 25          Freshmen
                                                Last Names beginning with A – Mas             8:00am – 11:00am
                                                Last Names beginning with Mat – Z              12:30pm – 3:30pm
Freshmen are required to attend from the beginning of their time slot and be present for the entire time block.  Los Osos Link Crew will provide a 3-hour campus/student orientation to ensure our newest Grizzlies are ready for their first day of school.  We will also hold an informative parent meeting in the Theatre at 8:00am and again at 12:30pm for the above alphabet groups.  This meeting will be approximately one hour to discuss the high school experience and supports in place for student success – at the conclusion of this meeting, parents are expected to leave campus since students will not be finished with their activities until 11:00am or 3:30pm.
Tuesday, July 26          Seniors
                                                Last Names beginning with A – Mas             8:00am – 9:30am
                                                Last Names beginning with Mat – Z              9:30am – 11:00am
Wednesday, July 27    Juniors
                                                Last Names beginning with A – Mas             8:00am – 9:30am
                                                Last Names beginning with Mat – Z              9:30am – 11:00am
Wednesday, July 27    Sophomores
                                                Last Names beginning with A – Mas             12:30pm – 2:00pm
                                                Last Names beginning with Mat – Z              2:00pm – 3:30pm
Monday, Aug 1             Make-up Day                                    8:00am – 11:00am
Finally, our staff is excited to welcome back your students and to work collaboratively to ensure all students have access to the resources and opportunities they need to be successful. Should you have any questions please do not hesitate to give us a call at (909) 477-6900.
Claws Up and Go W.I.L.D! 
Eric Cypher
Principal of Los Osos High School