Sherig-ool Dizizhikovich Oorzhak (Tuvan: Шериг-оол Дизижик оглу Ооржак, [ʃærɪɡɔːl dɪzɪʒɪɡovɪtʃ ɔːrʒʌk]; born July 24, 1942), is a Russian retired politician.

From December 1986 he was First Secretary in the Tuvan branch of the Communist Party of the Soviet Union, making him Tuva's de facto leader.

In August 1991 he was defeated by Kaadyr-ool Bicheldei in the race for Chairman of the Supreme Soviet of Tuva ASSR.

According to the Tuvan constitution, Tuva was "an independent state in association with Russia" and could "declare war and sign international agreements of its own will".

The political career of Oorzhak became uncertain after this, leading him to demonstrate his allegiance to the Kremlin by appointing Sergei Pugachev and Lyudmila Narusova to the Federation Council as representatives of Tuva.