Secret chambers are any room or area that is hidden away. Often these are accessed from a hidden door. Fictional secret chambers are often large areas (which sets them apart from a simple hidden room) and often contain entire secret libraries, hidden cult lairs, laboratories, dungeons, or treasure vaults. They are common elements in worldbuilding and are used in most if not all genres and world types.

When designing a secret chamber, consider how it was constructed, who knows about its location, for what purpose was it built, and how it is hidden. Many secret chambers are concealed behind a hidden door – often disguised as a bookcase, statue, or fireplace. Often there are clues, maps, riddles, or other elements that lead to the chamber or help to open it.

Secret chambers have been used in our own world to hide important and valuable items as well as people from those that would wish them harm.