The California Army National Guard is one of three components of the California National Guard, a reserve of the United States Army, and part of the National Guard of the United States. The California Army National Guard is composed of 18,450 soldiers. Nationwide, the Army National Guard comprises approximately one half of the US Army's available combat forces and approximately one third of its support organization. National coordination of various state National Guard units are maintained through the National Guard Bureau.

The California National Guard is part of the National Guard of the United States, a dual federal-state military reserve force. The CA National Guard has three components: the CA Army National Guard, CA Air National Guard, and CA State Guard. With a total strength of over 24,000 troops, it is the largest National Guard in the United States. As of January 2012, California National Guardsmen have been deployed overseas more than 38,000 times since 2001, during which time twenty-nine Guardsmen have been killed in Iraq and two have died in Afghanistan.