The Gambit System in Final Fantasy xII allows player to set the actions of each character during battle, which works similar to an easier version of programming language. By using a set of pre-programmed commands, a player is able to set specific reactions to battle for each character. Each Gambit consists of two component variables: a target, and an action. For example, the game initially gives players two commands for use in their Gambit instructions. One reads, "Leaders enemy: Attack" and the other reads "Party member [HP less than 70%]: Cure". The Gambits are listed in order of priority, and changing their order in the list will cause the character to act differently. If the first command is "Leader's enemy: Attack" and the second is "Party member [HP less than 70%]: Cure", the character will attack with the party leader as long as they are engaged in battle. Once the party leader's target has been eliminated or the leader disengages from battle, the second command will come into play. If any party member is below 70% health, the character with the aforementioned Gambit will cast Cure on them.

Different battle procedures would follow if the two commands were switched around, as the character will cease their attack and cast Cure on any party member with less than 70% health, and then resume attacking once all party members are at 70% health or more. There will be many different Gambits in the game to facilitate choosing any specific target, friend or foe, and then performing any action on it. Each character has a maximum of twelve available Gambit slots, which must be unlocked one at a time on the License board. Gambits are most often bought in Gambit shops, but they can also be found in chests.

Here is an example of a typical Gambit list used during the game:

Priority	Target	Action
1	Party Member [KO'd]	Cast Life
2	Party Member [HP less than 30%]	Cast Cura
3	Party Member [Darkness]	Use Eye Drops
4	Party Member [Slow]	Cast Esuna
5	Party Member [Poison]	Use Antidote
6	Yourself	Cast Protect
7	Yourself	Cast Haste
8	Yourself [MP less than 10%]	Use Ether
9	Undead Enemy	Use Phoenix Down
10	Flying Enemy	Cast Gravity
11	Enemy [Weak vs. Fire]	Cast Fira
12	Leader's Enemy	Attack

This Gambit setting makes keeping all party members alive and in good fighting condition the highest priority; reviving fallen characters, keeping the party's HP at a safe level, and removing status ailments. The next priority is the character supporting them self with Protect and Haste spells and MP replenishment, these will probably be the first commands done once entered into a battle since the conditions for the priority's above this one will not likely be on your characters at the start of a battle. The final priority is attacking enemies.

Giving undead and flying enemies special priority over all others ensures that the character will always treat them differently than "normal" enemies. If this character encounters a flying enemy which is also undead, they will treat them as undead, as the Undead Enemy Gambit is given a higher priority than the Flying Enemy Gambit. By giving attacking enemies the lowest priority, this character will cease attacking in the midst of battle the instant any other parameter arises and they will not resume attacking until that parameter has been rectified. Note that there is no specific qualifier following "Yourself" in the Protect and Haste Gambits. Therefore this character will cast Protect and Haste on themself the instant their Protect and Haste status wears off.