The rally was organized by local activists and the Belarusian diaspora in the Ukrainian capital.
Some protesters at the rally said they left Belarus to avoid the regime's harassment.
The protesters waved white-red-white flags of the Belarus opposition and chanted "Live long, Belarus", a chant which became widely known during the mass protests in Minsk and other Belarus cities last year.
Belarus has been subject to EU and U.S. sanctions since President Alexander Lukashenko cracked down on pro-democracy protests after a disputed election last year.
But Lukashenko's decision last week to intercept an international airliner in Belarusian airspace and arrest 26-year-old journalist Roman Protasevich, has brought threats of more serious action.
Most European countries told their aircraft to avoid Belarus airspace and banned Belarus carriers from their skies.
Ukraine also banned flights to and from Belarus.