Nikolayevka () is a rural locality (a selo) and the administrative center of Nikolayevsky Selsoviet, Mikhaylovsky District, Altai Krai, Russia. The population was 925 as of 2013. There are 9 streets.
Nikolayevka lies in the Kulunda Steppe to the east of lake Gornostalevo and close to the Russia-Kazakhstan border. It is located northwest of Mikhaylovskoye (the district's administrative centre) by road. Bastan is the nearest rural locality.