The Velykyi Kuialnyk (Ukrainian: Великий Куяльник) or Bolshoy Kuyalnik (Russian: Большой Куяльник) is a river in Podilsk and Berezivka Raions of Odesa Oblast, Ukraine.

[1] The urban-type settlements of Shyriaieve and Ivanivka are located along its banks.

Historically, the Velykyi Kuialnyk was navigable and, along with the Dniester, served as a route for transporting goods to the Black Sea, bypassing the cascades of the Dnieper River.

However, in 2007–2008, illegal sand diggers constructed a dam at the river’s mouth, which prevented it from emptying into the sea.

The dam has not been removed, resulting in the gradual drying of the estuary.