Ago or AGO may refer to:

• Ago Anderson (born 1972), Estonian actor
• Ago-Endrik Kerge (1939–2021), Estonian ballet dancer, ballet master, director and actor
• Ago of Friuli, 7th-century Duke of Friuli
• Ago Markvardt (born 1969), Estonian skier
• Ago Neo (1908–1982), Estonian wrestler
• Agó Páez (born 1954), Uruguayan plastic artist
• Ago Pajur (born 1962), Estonian historian
• Ago Roo (born 1946), Estonian actor
• Ago Ruus (born 1949). Estonian film cinematographer and director
• Ago Silde (born 1963), Estonian politician
• Agostino Carollo, Italian musician who released records as "Ago"
• Erbi Ago (born 1990), Albanian model
• Petrit Ago, Albanian civil servant
• Roberto Ago (1907–1995), Italian jurist

• Ago Bay, a bay in Japan
• Ago, Mie, a town in Japan
• Ago-Oba, electoral district in Nigeria
• Angola, ISO 3166-1 alpha-3 country code

• Ag-o (악어), a 1996 South Korean film
• AGO Flugzeugwerke, a German aircraft manufacturer
• AGO system, a manufacturing process for making stitchless shoes
• Alpha Gamma Omega, a national, Christ-Centered fraternity
• Adjutant General's Office or A.G.O.
• American Guild of Organists
• Argonaute proteins (AGO)
• Art Gallery of Ontario
• Attorney General's Office
• Attorney General of Ohio
• Attorney General of Oklahoma
• Attorney General of Ontario
• Attorney General of Oregon
• Auditor General of Ontario
• Australian Geospatial-Intelligence Organisation
• Operation A-Go (あ号作戦), Japanese plans for the Battle of the Philippine Sea during World War Two
• Silver(I,III) oxide (Ag₄O₄ or AgO)
• Silver(I) oxide (Ag₂O)
• Tainae language

• Agos, Armenian newspaper from Turkey
• Agos (TV series), Philippine TV series
• AGOS (Auxiliary General Ocean Surveillance Ship) of the US Navy; see Ocean Surveillance Ship