Kostiantynivka (Ukrainian: Костянтинівка; Russian: Константиновка) is a rural settlement in Voznesensk Raion in the north of Mykolaiv Oblast, Ukraine.

[1] Kostiantynivka is located on the left bank of the Southern Bug and is adjacent to the city of Pivdennoukrainsk.

[4] In 1816, Kostiantynivka became a military settlement which belonged to Yelisavetgradsky Uyezd of Kherson Governorate.

In 1923, uyezds in Ukrainian Soviet Socialist Republic were abolished, and the governorates were divided into okruhas.

In 1930, okruhas were abolished, and in 1931, Arbuzynka Raion, with the administrative center in Harbuzynka, was established.