The term Halloween, and its older spelling Hallowe'en, is shortened from All-hallow-even, as it is the evening before "All Hallows' Day" (also known as "All Saints' Day").

In Ireland, the name was All Hallows' Eve (often shortened to Hallow Eve), and though seldomly used today, it is still a well accepted label. Halloween was also sometimes called All Saints' Eve.

Halloween is also called Pooky or Punky Night in some parts of Ireland, presumably named after the púca, a mischievous spirit.

Another name associated to Halloween is Mischief Night