Maxim Osmidov (Max von Osmidoff; 1879–1952) – an architect. >>

Andrey Osokin (1984) – a pianist. >>

Sergey Osokin (1960) – professor, one of the best Latvian pianists. >>

Yelena (Alyona) Ostapenko (1997) – a tennis player. >>

Leonid S Ostrouchow (1867-1937) – a senior advisor to the Livonia governorate, public and theatrical figure, teacher. >>

Nikolay Ovcharov (1868–1933) – a colonel. >>

Sergey Ovsyukov (1941) – Doctor of Engineering (Dr. sc. ing.), Docent of the Riga Polytechnic Institute (from 1990 – Riga Technical University). >>

Ilga Ozish (1945-2023) – programmer, public figure, well-known human rights activist, one of the founders and long-term member of the Latvian Human Rights Committee. >>

Nikolai Osmidoff (1850-1938) – professor of the Riga Polytechnik Institute, famous specialisn in electrical engineering.  >>

Marianna Ozolinya (1939) – from 1973 to 2013 Curator of the Museum of St Peter's Church in Riga, poet. >>