The attackers hurled teargas and smoke bombs at the 300 marchers as they walked along along the Dnipro river bank in the Ukrainian capital on Saturday morning.
The Interfax news agency reported that five police officers were injured, while other local media reported four marchers were hurt.
Several hundred riot police formed a cordon to keep marchers and opponents apart, following a warning that the event was threatened by far-right groups.
Some opponents to gay rights tried to break through the cordon. Some demonstrators were attacked after the march dispersed.
MP Serhiy Leshchenko said on Twitter that 25 to 30 “hooligans” were arrested.
On Friday, the organisers for KyivPride2015 said the march would go ahead despite warnings from the mayor, Vitaly Klitschko, who advised that the event be cancelled because of a threat of violence from far-right groups.
As in other parts of the former Soviet Union, animosity to gay people persists. The tensions are aggravated by opponents’ claims that Ukraine’s political turn toward the west will promote gay marriage.