Sernur (Russian: Се́рнур; Meadow Mari: Шернур, Šernur) is an urban locality (an urban-type settlement) and the administrative center of Sernursky District of the Mari El Republic, Russia.

As of the 2010 Census, its population was 8,686.

[2] Within the framework of administrative divisions, Sernur serves as the administrative center of Sernursky District.

[3] As an administrative division, the urban-type settlement of Sernur, together with three rural localities, is incorporated within Sernursky District as Sernur Urban-Type Settlement[3] (an administrative division of the district).

[1] As a municipal division, Sernur Urban-Type Settlement is incorporated within Sernursky Municipal District as Sernur Urban Settlement.