Kalyazinsky Uyezd (Калязинский уезд) was one of the subdivisions of the Tver Governorate of the Russian Empire. It was situated in the eastern part of the governorate. Its administrative centre was Kalyazin. In terms of present-day administrative borders, the territory of Kalyazinsky Uyezd is divided between the Kalyazinsky, Kashinsky and Kimrsky districts of Tver Oblast and Taldomsky District of Moscow Oblast.