College of the Siskiyous (COS) is a public two-year community college with campus is located in Weed, and Yreka, California in Siskiyou County in Northern California. It is part of the California Community Colleges System and has an enrollment of approximately 3,000 students, including part-time students. It is the northernmost college in the state of California and the only college in Siskiyou County. It lies in the service area of California State University, Chico. It is one of only ten community colleges in California that provide on-campus dormitories for students.

COS was founded in 1957 after a special election. Buildings on the current location first opened their doors on September 8, 1959. Facilities at COS include HerschelnMeredith Stadium for football and track and field events, Ford Theater for theatrical performances and Rural Health Science Institute. COS also is known for its administration of justice program and fire academy, the best in California. The athletic mascot is the Eagle.

Music, Theater, Media Communications, and Visual Arts are of significant importance to the College of the Siskiyous.

Nursing programs, including the new LVN to RN step up program are a hallmark of the College of the Siskiyous.

A common misconception about COS is that it is named after Siskiyou County. But it is actually named after the Siskiyou Mountains, a mountain range that runs along the California-Oregon border, which is referred to as "the Siskiyous" (referenced in the plural form, instead of singular).

The president of COS is Dr. Randall Lawrence.

Famous alumni include Dan Hawkins, the former head football coach at the University of Colorado.

Men's Basketball Team

Under the direction of Legendary Coach Ed Madec the Men's Basketball team was one of the best Junior College teams in California from 2002-2006. They reached the California Final Four in 2004 and 2005.