Oleg Sõnajalg was an Estonian entrepreneur

Oleg Sõnajalg, together with his brother Andres Sõnajalg, has been one of Estonia's best-known and most ambitious wind energy developers. They have also previously worked in the real estate sector, among other things. Their company, Eleon AS, and other wants to build large and innovative wind farms in Estonia, including the much-talked-about Aidu wind farm in Ida-Viru County. It was completed last year. They have stated that they will also develop wind turbine technology themselves.

He and his wife Viiv raised five children.

He was in a relationship with Catherine Raudvere, 39 years younger.

They first met in October 2021.