Umi or UMI may refer to:

• Umi, Iran, a village in Razavi Khorasan Province, Iran
• Umi, Fukuoka, a town in Japan

• Umi-a-Liloa, king of the island of Hawaii
• Umi Dachlan, Indonesian female artist
• Umi Garrett, American female pianist.
• Umi (singer), Tierra Umi Wilson (born 1999), American singer and songwriter
• "Umi" (song), ("海", literally 'ocean') Japanese language song by Japanese band Lead, 2007
• Umi Tenjin, Japanese voice actress

• Umi Ryuzaki, a character in the fictional manga series Magic Knight Rayearth
• Umi Sonoda, a character in Love Live! School Idol Project

• Unified Media Interface, a computer interconnect used in AMD APU systems
• Italian Mathematical Union (Italian: Unione Matematica Italiana), an Italian mathematics society
• Uganda Management Institute, a business education institute in Kampala, Uganda
• Union Mundial pro Interlingua, an organization related to the international language Interlingua
• Methodist University of Indonesia (Universitas Methodist Indonesia), a university in Medan, Indonesia
• University Microfilms International, a microfilm publisher
• Urban Ministries, Inc., an American Christian media company
• Ursa Minor (UMi), a constellation
• Unique molecular identifier, a technique used in molecular biology research
• United States Minor Outlying Islands, ISO_3166 Alpha-3 code of United States Minor Outlying Islands consisting of eight United States insular areas in the Pacific Ocean

• Umi, a sculpture by Daniel Popper

• Former name of Umidigi, a Chinese mobile phone manufacturer