The word shillelagh can mean:

• Shillelagh (weapon), a type of club.
• Shillelagh, County Wicklow, a town in Ireland.
• The MGM-51 Shillelagh missile.
• Shillelagh, a computer technology code name for Source Mage GNU/Linux 0.5
• Jeweled Shillelagh, a trophy associated with the USC - Notre Dame football rivalry.
• Shillelagh Trophy, a trophy associated with the Purdue - Notre Dame football rivalry.
• It's the Same Old Shillelagh, an Irish song.