Sergachsky District () is an administrative district (raion), one of the forty in Nizhny Novgorod Oblast, Russia. Municipally, it is incorporated as Sergachsky Municipal District. It is located in the southeast of the oblast. The area of the district is . Its administrative center is the town of Sergach. Population: 31,296 (2010 Census); The population of Sergach accounts for 68.3% of the district's total population.
The district was established in 1929.