Dominic "Dom" Santiago is a supporting character in the Gears of War franchise. One of the main members of Delta Squad and the character controlled by player two in co-op mode, Dom is Marcus Fenix's right-hand man. He is voiced by Carlos Ferro.

Dominic is a protagonist in the Gears of War franchise and the wingman of Marcus Fenix. In co-op play, the second player will play as Dom.

When Dominic was just a small lad, his two best friends were his older brother, Carlos and Marcus. He enlisted to fight in the war at the young age of sixteen and was a dedicated soldier. One of Victor Hoffman's favorites. He went through special training and became a commando which is where he met Bernie Mataki for the first time. When Carlos Santiago died at the battle of Aspho Fields Dom went into a depression. He couldn't imagine life without his brother.

Dom was a patriotic soldier who served alongside Marcus Fenix. Never to doubt his country or its leaders, Dom was shaken after Marcus Fenix was imprisoned after he attempted to save his father but disobeyed orders. The seemingly endless war against the Locust has made Dom weary of war. A family man, Dom is also concerned about his family whom he lost contact with when the Locust attacked on Emergence Day. Fearing the worst, the fight against the Locust has become personal for Dom.

When Marcus Fenix was on trial, Dom testified for his friend's actions during the war. Because of this, Fenix was spared the death penalty, yet the psychological effects of his friend's imprisonment were large. Four years after Emergence Day, Dom discovered that the prison Marcus was being held in was attacked by the Locust. He arrived and helped Fenix escape. Fenix was going to be left to rot alone in the prison, all the other prisoners had been set free. Dom then convinced his commanding officer, Lieutenant Kim, to allow Fenix to join their team, Delta Squad.

After learning about his situation in the first game, Gears of War 2 explore more of Dom's story. In the game, Dom continues to search for his wife Maria whom he lost contact with on Emergence Day.

Dom appears in the announcement trailer for Gears of War 3 running away from oncoming fire from Locust. A grenade blast knocks him down and he turns his head to the camera, revealing that he has grown a thick beard since the end of Gears of War 2. A locust walked up to him and prepares its rifle as Dom slowly lays back as if he is accepting death. Suddenly, Marcus saves Dom at the last second with a sawed-off shotgun and he is given a pendulum lancer by Anya and then proceeds to help fight the growing forces of the Locust and Lambent as Cole and Baird arrive to assist.

- Dominic Santiago is voiced by Carlos Ferro.
- Dominic carries a combat knife attached to his chest armor, though he never uses it.
- His wife Maria Santiago makes an appearance in Gears of War 2.
- He has a proficiency at gardening and, most notably, the propagation of radishes.
- Dom grows a kickass beard at some point in between Gears of War 2 and Gears of War 3.