Reflex trigger are the conditions listed on a card that govern when a model will carry out a reflex action. A model may only carry out one reflex action in a reflex phase, unless otherwise stated.

The reflex action must be taken the first time a reflex trigger is met. If many model's reflex triggers are met at the same time, the reflex player decides which order to carry out actions. If, as a result of a reflex trigger, the conditions for subsequent models are no longer valid, then reflex actions are retained.

A model can have multiple reflex triggers through abilities and traits. An enemy can trigger multiple reflex actions from  that model providing the conditions are met twice. For example, a reflex action triggered by movement may be met once by the initial square of movement. After the reflex action is resolved, a subsequent square of movement will trigger another refelx action, provided the conditions are still met.