Guard Tower is a University technology.
- Building: University
- Age: Castle Age
- Cost: 100 food, 250 wood
- Research time: 30 seconds
- Available to: 51 of 56 civilizations. Missing for: Cumans, Goths, Huns, Mapuche, Sicilians.
Upgrades Watch Towers to Guard Towers, which have more hit points and attack.
Figures from the game data for Update 185872 (September 2026), at the time of publishing.