| En Name: | Ruzayevsky District |
| Ru Name: | Рузаевский район |
| Loc Name1: | Орозаень аймак |
| Loc Lang1: | Moksha |
| Loc Name2: | Рузайбуе |
| Loc Lang2: | Erzya |
| Image View: | Ruzayevsky District, Mordovia, Russia - panoramio.jpg |
| Coordinates: | 54.0667°N 101°W |
| Image Coa: | Ruzaevka COA (2020).png |
| Federal Subject: | Republic of Mordovia |
| Adm Data As Of: | June 2015 |
| Adm Ctr Type: | town |
| Adm Ctr Name: | Ruzayevka |
| Selsoviet Type1: | Selsoviets |
| No Of Selsoviets Type1: | 20 |
| No Of Rural Localities: | 63 |
| Mun Data As Of: | June 2010 |
| Mun Formation1: | Ruzayevsky Municipal District |
| Mun Formation1 No Of Urban Settlements: | 1 |
| Mun Formation1 No Of Rural Settlements: | 20 |
| Area Km2: | 1089.5 |
| Pop 2010Census: | 18859 |
| Urban Pop 2010Census: | 0% |
| Rural Pop 2010Census: | 100% |
| Website: | http://ruzaevka-rm.ru |
| Date: | January 2010 |
| Bodystyle: | width:23.5em |
| Population of Ruzayevsky District | |
| Label1: | 2010 Census |
| Data1: | 18,859 |
| Label2: | 2002 Census |
| Data2: | 19,091 |
| Label3: | 1989 Census |
| Data3: | 21,591 |
| Label4: | 1979 Census |
| Data4: | 25,754 |
Ruzayevsky District (Russian: Руза́евский райо́н; Moksha: Орозаень аймак, Orozajeń ajmak; Erzya: Рузайбуе, Ruzajbuje) is an administrative[1] and municipal[2] district (raion), one of the twenty-two in the Republic of Mordovia, Russia. It is located in the southern and central parts of the republic and borders with Staroshaygovsky and Lyambirsky Districts in the north, the territory of the city of republic significance of Saransk and Kochkurovsky District in the east, Penza Oblast in the south, and with Kadoshkinsky and Insarsky Districts in the west. The area of the district is 1089.5km2. Its administrative center is the town of Ruzayevka (which is not administratively a part of the district).[3] As of the 2010 Census, the total population of the district was 18,859.
Within the framework of administrative divisions, Ruzayevsky District is one of the twenty-two in the republic. The district is divided into twenty selsoviets which comprise sixty-three rural localities. The town of Ruzayevka serves as its administrative center, despite being incorporated separately as a town of republic significance—an administrative unit with the status equal to that of the districts.
As a municipal division, the district is incorporated as Ruzayevsky Municipal District, with the town of republic significance of Ruzayevka being incorporated within it as Ruzayevka Urban Settlement. Its twenty selsoviets are incorporated as twenty rural settlements within the municipal district. The town of Ruzayevka serves as the administrative center of the municipal district as well.