MSY or msy can mean:

• Maximum sustainable yield
• IATA airport code for Louis Armstrong New Orleans International Airport
• The Mount School, York, United Kingdom
• Motor sailing yacht, a ship prefix for a yacht that can use a motor for propulsion and also sail
• Macao Sam Yuk Middle School

• Mahanay Tower
• Mahan class destroyer
• Mahan Dal
• Mahander Nagpal
• Mahan District
• Mahane Israel, Jerusalem
• Mahaney
• Mahane Yehuda market
• Mahaney's theorem
• Mahan folk song
• Mahanga
• Mahanga (Odisha Vidhan Sabha constituency)
• Mahango Game Park
• Mahango National Park
• Mahan, Hamadan
• Mahan (horse)
• Mahani
• Mahani, Bushehr
• Mahani (disambiguation)
• Mahanirvani Akhara
• Mahani, South Khorasan
• Mahankali Seetharama Rao
• Mahankali seetharama rao
• Mahankal, Sindhupalchok
• Mahan Kermanshah F.C.