W5

W5 may refer to:

*W5, a form used by the United States Internal Revenue Service for filing Earned Income Credit information.
*W5, aka IC 1848, a large star-forming region in Cassiopeia lying about 7,000 light years away.
*W5 nuclear warhead, another name for the Mark 5 nuclear bomb.
*London W5, a London postal district.

*W-FIVE, a Canadian television news program.

*The Five Ws of journalism: Who? What? Where? When? and Why? (and often How?)