The Adjutant General of Texas is the commander and chief executive officer of the Texas Military Department, the executive department of the Texas Military Forces. The adjutant general's position of authority over Texas Military Forces is second only to the commander-in-chief, the governor of Texas. This position is analogous to the United States secretary of defense. The adjutant general of Texas is appointed by the governor of Texas with the advice and consent of the Texas Senate from Texas Government Code Title 4, Subtitle C, Chapter 437.003.

The Texas Military Department (TMD) is an executive branch agency of the Texas government. Along with the Texas Department of Public Safety, it is charged with providing the security of Texas, which has the second largest population, border, and economy in the United States. It also provides administration of the Texas Military Forces (TXMF), the principal instrument through which it executes security policy. TXMF currently include the Texas Army National Guard, Texas Air National Guard, and Texas State Guard. It formerly included the Texas Rangers, Texas Army, Texas Navy, and Texas Marines.