Yuri Sidyakov (1953) – Doctor of Philology, Associate Professor of the Slavic Department of the University of Latvia. >>

Igor Sikorsky (1889–1972)  –  a founder of Russian aircraft construction,  aircraft constructor in Russo-Balt, then became a distinguished American helicopter builder. >>

Yuri Silov (1950–2018) –  an athlete, two-time Olympic medalist. >>

Silvester (secural name Ivan Kharun, 1914–2000) – an Archbishop of the Orthodox church in Amerika. >>

Pavel Sinaisky (1860–?) – an arrchpriest. >>

Vasily Sinaysky (1947) –  a famous conductor. >>

Vasily Sinaisky (1876–1949) – professor of  the  University of Latvia  from 1922 to 1944, where he read lectures on Civil law.   >>

Natalia Sinaysky (1914-2006) – a daughter of Professor Sinaysky. Worked as  specialisit in the fields of customs and tax law in the institutions of the European  Economic Community. >>

Alexander Sirotin (1883-?) –  a member of the People's Council of Latvia in 1919-1920, public figure, master ceramist. >>

Polina Sjakste (1929–2019) – a Docent of the Riga Medical Institute, from 1990 – Latvian Medical Academy. >>