Olga or Olha is a Slavic feminine given name.
Olga or OLGA may also refer to:
- Olga of Kiev was a ruler of Kievan Rus' as regent (945–c. 963).
- Grand Duchess Olga Alexandrovna of Russia (1882 - 1960), the younger sister of Emperor Nicholas II Romanov of Russia.
- Grand Duchess Olga Nikolaevna of Russia (1895 - 1918), the eldest daughter of Emperor Nicholas II Romanov of Russia and Empress Alexandra Feodorovna (Alix of Hesse).
- Mount Olga (Kata Tjuta), a mountain-like rock formation in central Australia
- Olga, Russia, an urban-type settlement in Primorsky Krai
- Olga Bay, a bay of the Sea of Japan in Primorsky Krai
- Olga River, a river in Primorsky Krai
- United States
- Olga Bay, Alaska, a bay on the south end of Kodiak Island
- Olga, Florida, a census-designated place
- Olga, Kentucky
- Olga, Washington, a village on Orcas Island
- Olha, Manitoba, a village
- Olga, Greece, a settlement
Science and technology
- Online Gamers Anonymous
- On-line Guitar Archive, an online resource for guitar chords and tablature
- OLGA (technology), oil and gas simulator
- Organic Land Grid Array, a silicon layer or substrate between a microprocessor's die and interposer
- Olga Bay Larch, a species of larch
- Tropical Storm Olga (disambiguation), the name of several different storm systems
- 304 Olga, a main belt asteroid
- MV Olga, a German coaster in service 1927-59
- Olga, the nickname of the Sikorsky S-64 skycrane used to carry the radio antennae to the top of the CN Tower.
- Olga (opera) (2006), by Jorge Antunes, based on the life of Olga Benário Prestes
- Olga (film), a 2004 film directed by Jayme Monjardim and based on the life of Olga Benário Prestes
- Michael Algar, nickname "Olga" (born 1962), singer of UK punk rock band Toy Dolls