Olga may refer to:

• Olga (name), a given name, including a list of people and fictional characters named Olga or Olha
• Michael Algar (born 1962), English singer also known as "Olga"

• Olga, Russia, an urban-type settlement in Primorsky Krai
• Olga Bay, a bay of the Sea of Japan in Primorsky Krai
• Olga (river), Primorsky Krai

• Olga, Florida, an unincorporated community and census-designated place
• Olga, Kentucky, an unincorporated community
• Olga, Missouri, an unincorporated community
• Olga, Washington, an unincorporated community
• Olga Bay, Alaska, a bay on the south end of Kodiak Island
• Olga, a neighborhood of South Pasadena, California

• Kata Tjuta, Northern Territory, Australia, also known as the Olgas, a group of domed rock formations
  • Mount Olga, the tallest of these rock formations
• Olga, Greece, a settlement
• 304 Olga, a main belt asteroid

• Olga (opera), a 2006 Brazilian opera about Olga Benário Prestes
• Olga (2004 film), a 2004 Brazilian biopic of Benário
• Olga (2021 film), a Franco-Ukrainian-language Swiss drama
• Olga TV, a British independent television production company
• On-line Guitar Archive, a former online resource for guitar chords and tablature

• OLGA (technology), an oil and gas simulator
• Tropical Storm Olga, the name of several tropical cyclones
• MV Olga, a German coaster in service 1927–59
• Olga (horse), an equine recipient of the Dickin Medal
• Führerhauptquartier Olga, an unfinished German World War II bunker facility planned for Hitler's use near Orsha, Soviet Union

• Oga (disambiguation)