Nikolayevsk is a town in Volgograd Oblast, Russia.
Nikolayevsk or Nikolaevsk may also refer to:
- Nikolayevsk Urban Settlement, a municipal formation which the town of district significance of Nikolayevsk in Nikolayevsky District of Volgograd Oblast, Russia is incorporated as
- Nikolaevsk, Alaska, a town in Alaska, United States
- Nikolayevsk-on-Amur, a town in Khabarovsk Krai, Russia