EIEIO

EIEIO may refer to:

• The refrain to the children's song, "Old MacDonald Had a Farm"
• Enforce In-order Execution of I/O, a machine instruction used on the PowerPC computer processor
• Computer bought the farm, an error message with symbol EIEIO, from the GNU Hurd operating system
• EIEIO, the Enhanced Implementation of Emacs Interpreted Objects, an object-oriented elisp system based on the Common Lisp Object System
• "E-I-E-I-O", an episode of Barney & Friends from the fourth season of the show