| Raymond S. Kellis High School | |
| Motto: | Cougar Pride! Is It In You? |
| Location: | 8990 W. Orangewood Avenue, Glendale, Arizona, United States of America |
| Type: | Public secondary |
| Established: | 2004 |
| Principal: | Tony Vining |
| Faculty: | 119 |
| Mascot: | Cougar |
| Rival: | Peoria High School |
| Enrollment: | 1,697 (2023-2024)[1] |
| Ratio: | 20.56 |
| Staff: | 82.54 (FTE) |
| Colors: | Vegas gold, navy blue, black |
| Free Label: | AIA Class |
| Free Text: | 5A |
Raymond S. Kellis High School is a public secondary school located in Glendale, Arizona, United States, part of the Peoria Unified School District. It opened in August 2004 due to overcrowding at Peoria High School and rapid population growth in the surrounding area. The school is the district's fourth-largest, with approximately 1,850 students.
Kellis High School is located near State Farm Stadium, home of the Arizona Cardinals, and Desert Diamond Arena, former home of the Arizona Coyotes.