Tattinsky District (; , Taatta uluuha) is an administrative and municipal district (raion, or ulus), one of the thirty-four in the Sakha Republic, Russia. It is located in the eastern central part of the republic and borders with Tomponsky District in the north and east, Ust-Maysky District in the south, Churapchinsky District in the southwest, and with Ust-Aldansky District in the northwest. The area of the district is . Its administrative center is the rural locality (a selo) of Ytyk-Kyuyol. Population: 16,601 (2002 Census); The population of Ytyk-Kyuyol accounts for 39.6% of the district's total population.
The landscape of the district is mostly flat. Its main rivers include the Amga, the Aldan and the Tatta, a tributary of the latter.
Average January temperature ranges from and average July temperature is . Annual precipitation is .
The district was established on May 25, 1930. Until 1990, it was called Alexeyevsky ().
As of the 2021 Census, the ethnic composition was as follows:
The economy of the district is mostly based on agriculture.
<small>Divisional source:</small><br /> <br/> <small>*Administrative centers are shown in bold</small>