Mykolaivka Raion (Ukrainian: Миколаївський район) was a raion (district) in Odesa Oblast of Ukraine.

Its administrative center was the urban-type settlement of Mykolaivka.

The raion was abolished on 18 July 2020 as part of the administrative reform of Ukraine, which reduced the number of raions of Odesa Oblast to seven.

[1][2] The last estimate of the raion population was 15,399 (2020 est.).

[3] At the time of disestablishment, the raion consisted of three hromadas:[4]