The card with the Secret ability is played face-down, with its effect triggering when a certain condition is fulfilled. Players can keep track of how many secrets they have in play, as they appear above the hero as "?". Secrets are considered spells and can be countered through the use of abilities like or copied via .
- Since they are considered spells, they are affected by Spell Damage.
- Duplicate secrets cannot be in play by the same player.
- Multiple secrets may trigger at once, but trigger in the order in which they were played.
- A player may only have five secrets in play at a time.
- If a minion has a battlecry at the time it is played, the battlecry will trigger, then the secret.
Below is a list of all cards with the secret mechanic.
- Note: For the purposes of this list, only collectible cards are listed.