A team bonus is a specific civilization bonus in Age of Empires II that applies to both the player's civilization and all allied players from the start of each game. Two of the same team bonuses do not stack, but a team bonus can stack with another bonus. It is also important to note that should a player be defeated or resigns, their team bonus remains active for their allies.

The complete list of all team bonuses:

Note that while not technically a team bonus, the Berbers' unique technology Kasbah can be considered a team bonus as well since it - just like regular team bonuses - affects the entire team. The Vietnamese also have a technology that benefits the entire team: Paper Money. But since it is of one-time use it cannot really be considered a team bonus.

Out of all 40 unique units in the game, three are available as team bonuses: the Condottiero, the Imperial Skirmisher, and the Genitour. These are often used to supplement lacking unit lines (for example Condottieri can make up for the Persians' lacking Militia line, and Aztec Imperial Skirmishers surpass the Aztec Arbalest), or to cover a niche, such as in a late Imperial Age trash game.