Coordinates: 46°58′N 32°0′E / 46.967°N 32°E / 46.967; 32

Mykolaiv (Ukrainian: Миколаїв Ukrainian pronunciation: [mɪkoˈlɑjiu̯]), also known as Nikolayev (from Russian Николаев), is a city in southern Ukraine, administrative center of the Mykolaiv Oblast. Mykolaiv is the main ship building center of the Black Sea, and, arguably, the whole Eastern Europe; also a riverport.

Mykolaiv's orderly layout reflects the fact that its development has been well planned from the founding of the city. Its main streets, including the three main East-West Avenues, (including Lenin Prospect shown in the photo to the right) are very wide and tree lined. A significant part of Mykolaiv's land area is beautiful parks. Park Pobedy (Victory) is a large park on the peninsula just north of the city center of Mykolaiv, on the North side of the Inhul river.

Mykolaiv has a population of about 500,000.

There are several variations of the city's name. In Ukrainian, the city is named Микола́їв, for which the transliteration is Mykolaiv, or, more rarely, Mykolayiv. The Russian name is Никола́ев, which transliterates as Nikolaev or Nikolayev.