Mykolaiv Raion (Ukrainian: Миколаївський район) was a raion in Lviv Oblast in western Ukraine. Its administrative center was Mykolaiv. The raion was abolished on 18 July 2020 as part of the administrative reform of Ukraine, which reduced the number of raions of Lviv Oblast to seven. The last estimate of the raion population was 62,537 (2020 est.).
It was established in 1939.