Tandinsky District (; , Tañdñ kojuun) is an administrative and municipal district (raion, or kozhuun), one of the seventeen in the Tuva Republic, Russia. It is located in the center of the republic. The area of the district is . Its administrative center is the rural locality (a selo) of Bay-Khaak. Population: 13,827 (2002 Census); The population of Bay-Khaak accounts for 23.1% of the district's total population.