Olly olly oxen free (and similar spellings) is a catchphrase used in the children's game hide and seek to indicate that players who are hiding can come out into the open without losing the game. It is thought to derive from the phrase "All ye, all ye 'outs' in free;" in other words: all who are "out" may come in without penalty.[1]
The phrase can also be used to coordinate hidden players in the game kick the can, in which a group of people hide within a given radius and a "seeker" is left to guard a can filled with rocks. The seeker has to try to find the "hiders" without allowing them to sneak in and kick the can. In many areas the phrase used is "All-y all-y in come free" which is a way to tell the remainder of hidden players that is time to regroup in order to restart the game. The phrase is announced by a hider who successfully sneaks in and kicks the can.
Another phrase that has a similar meaning and possibly similar root is "Come out, come out, wherever you are!".
