| Armijo High School | |
| Size: | 200px |
| Location: | 824 Washington Street Fairfield, California 94533 |
| Country: | USA |
| Coordinates: | 38.251°N -122.038°W |
| Pushpin Map: | California#USA |
| Principal: | John McMorris [1] |
| Faculty: | 89.17 (FTE) |
| Ratio: | 23.64 |
| Nickname: | Royals |
| Motto: | All students can grow and achieve. It is everyone's responsibility to see that the opportunity is present. |
| Accreditation: | Western Association of Schools and Colleges[2] International Baccalaureate[3] |
| Conference: | CIF Sac-Joaquin Section Division I[4] |
| Mascot: | The Royals, Lion |
| Team Name: | Armijo Royals[5] |
| Enrollment: | 2,108 (2018–19)[6] |
| Publication: | The Armijo Signal |
| Yearbook: | La Mezcla |
| Established: | 1891[7] |
| Free Label: | Former name |
| Free: | Armijo Union High School[8] |
Armijo High School is a public secondary school located in Fairfield, California, United States. It is the oldest of the three high schools in the Fairfield-Suisun Unified School District, the other two being Fairfield High School and Angelo Rodriguez High School. It is named after the Armijo family, who purchased one of the original six land grants in Solano County awarded to General Mariano Vallejo. The school serves about 2600 students in grades 9 to 12 from the central part of Fairfield and Suisun City.
The school started in 1891 with 30 students in a single classroom located in the Crystal Elementary School building. In 1893, a separate wooden building was built for use as the high school. In 1915, the school moved to a large stone building on Union Avenue in downtown Fairfield that is now used as the Solano County courthouse. It stayed there for nearly 50 years until construction was completed in 1964 on a newer facility located on Washington Street, roughly two blocks from the Union Avenue location. In 2019, the Fairfield-Suisun School District board voted unanimously to replace the "Armijo Indian" mascot. As of 2020, the school's mascot is "The Royals".