Sergey Vasilievich Yakhnyuk (Russian: Сергей Васильевич Яхнюк; born 3 July 1962, Altynivka, Sumy Oblast) is a Russian political figure and a deputy of the 7th and 8th State Dumas.

On September 19, 1999, he was elected Head of Administration of the Priozersky District of the Leningrad Oblast.

In 2017, following the resignation of Sergey Naryshkin in order to become direct of the Foreign Intelligence Service, Yakhnyuk was elected Deputy of the 7th State Duma in the Kingisepp by-election.

In September 2021, he was re-elected in Kingisepp as deputy for the 8th State Duma.

[2][3][4] He was sanctioned by the UK government on 11 March 2022 in relation to the Russo-Ukrainian War.