Jassy may refer to:

• Iași, a city in north-eastern Romania, former capital of the Principality of Moldavia

• Treaty of Jassy, a pact between Russian Empire and Ottoman Empire ending the Russo-Turkish War (1787–1792)
• First Jassy–Kishinev Offensive and Second Jassy–Kishinev Offensive, two 1944 World War II major offensives

• Jassy (surname), several people
• Jasz people, an ethnic group in Hungary, of Ossetic origin

• Adath Jeshurun of Jassy Synagogue, a defunct synagogue
• Jassy, a novel by Norah Lofts
• Jassy (film), a 1947 British film melodrama adaptation of the novel

• Iasi (disambiguation)
• Yassy (disambiguation)