The Texas State Guard (TXSG) mission as a branch of the Texas Military Forces is to provide mission-ready military forces to assist State and local authorities in times of state emergencies, with homeland security and community service through Defense Support to Civil Authorities (DSCA). To augment the other two branches of the Texas Military Forces, the Texas Army National Guard and Texas Air National Guard as force multipliers. Missions are directed by the Commander in Chief of the Texas Military Forces the Governor of Texas and commanded by the Texas Adjutant General.

The TXSG has four major Sub-Commands: Army, Air, Maritime and Medical.

"TEXANS SERVING TEXAS"

Army - To provide trained soldiers for Defense Support to Civil Authorities (DSCA), support the Texas Army National Guard, and non-governmental organizations (NGO).

Air - The mission of the Air Wings is to provide mission-capable airmen as a force multiplier for the Texas Air National Guard and for other missions in support of homeland security through Defense Support to Civil Authorities (DSCA).

Maritime - The mission of the Texas Maritime Regiment (TMR) is provide highly trained military personal for Defense Support to Civil Authorities (DSCA), for operations in the maritime, littoral, and riverine environments in support of homeland defense and in response to man-made or natural disasters.

Medical - The mission of the Texas Medical Brigade (TMB) is to augment health and medical support in times of need. TMB maintains a highly trained force that is rapidly deployable to provide appropriately qualified Health, Medical and Support personnel in accordance with the Defense Support of Civil Authorities (DSCA) missions.