Shillelagh

• Shillelagh (club), a type of hand weapon
• Shillelagh, County Wicklow, a town in Ireland
• The MGM-51 Shillelagh missile
• Shillelagh, the code name for Source Mage GNU/Linux 0.5
• It's the Same Old Shillelagh, an Irish song

In sport:

• Jeweled Shillelagh, a trophy associated with the USC - Notre Dame college football rivalry
• Shillelagh Trophy, a trophy associated with the Purdue - Notre Dame college football rivalry