Sidkeong Namgyal (Sikkimese: སྲིད་སཀྱོང་རྣམ་རྒྱལ་; Wylie: srid skyong rnam rgyal) (1819–1874) was king of Sikkim from 1863 to 1874.

He was son of Tsugphud Namgyal and was succeeded by his half-brother Thutob Namgyal.

[1][2] His mother was the second wife of his father, a Tibetan lady, sister of the Tashi Lama.

[citation needed] It was Sidkeong Namgyal who signed the Treaty of Tumlong with the British in 1861, his father having abdicated rather than return to surrender to the force of Sir Ashley Eden.

[3] This biography of a member of an Indian royal house is a stub.