Whitsunday, also known as Whitsun, is the celebration in England of the Christian feast of Pentecost, observed 7 weeks after Easter.

Whitsunday, Whitsundays and Whit Sunday may also refer to:

• One of the Scottish term days, always falling in modern times on 15 May

• Whitsunday Islands, an island group in Queensland
• Whitsunday Islands National Park in Queensland
• Whitsunday Island, the largest of the Whitsunday Islands
• Whitsunday Region, a local government area located in North Queensland, Australia
• Whitsundays, Queensland, a locality in the Whitsunday Region which includes the Whitsunday Islands
• Electoral district of Whitsunday, an electoral division in the Legislative Assembly of Queensland, Australia
• Shire of Whitsunday, a former local government area located in North Queensland

• Whitsunday wire eel, found in Australia