An impossible bottle is a type of mechanical puzzle. It is a bottle that has an object inside of it which doesn't appear like it could normally fit inside of a bottle. The ship in a bottle is probable the most well known type of impossible bottle but other common objects to find include matchboxes, [[deck of cards|decks of cards], tennis balls, racketballs, rubik's cubes, padlocks, knots and scissors.

In nearly every impossible bottle, the object inside has been carefully dissasembled and reassembled inside the bottle. For example, to get a deck of cards inside a bottle, you roll up the empty box and stick it in first, then insert each card one at a time. Using some long forcepts and other tools you can get everything back together again and the result is something that looks impossible unless you know the secret.