Glenn H. Randall Sr. (1908-1992) was a professional horse trainer, best known for training the horse Trigger for the television series The Roy Rogers Show. He developed over 30 hand commands to which the palomino responded.^[1] Randall Sr. also trained Gene Autry's horse Champion the Wonder Horse.^[2]

His other work as a horse trainer for television and film includes the 1956 film Stranger at My Door and the 1959 film Ben-Hur.^[1][3] Starting months before photography began, he trained around 40 horses for Ben-Hur, including the four whites (Altair, Rigel, Antares, and Aldebran) that Charlton Heston drove in the chariot race.^[4] Glenn Sr. later worked as a wrangler on the 1979 film The Black Stallion and its 1983 sequel The Black Stallion Returns.

His son Glenn H. Randall Jr., also known as "J.R.", was also a horse trainer as well as a stunt performer and stunt coordinator who was active from 1959 to 2000. Randall Sr.'s son Corky Randall was also involved in the industry.

• The Roy Rogers Show (101 episodes, 1951-1957), horse trainer
• Stranger at My Door (1956), horse trainer (uncredited)
• Ben-Hur (1959), horse trainer (uncredited)
• Toby Tyler or 10 Weeks with a Circus (1960), horse trainer (uncredited)
• The Black Stallion (1979), wrangler
• The Black Stallion Returns (1983), wrangler (uncredited)