Štrbački buk (Serbian Cyrillic: Штрбачки бyк) waterfall is a 25m high waterfall on the Una River (296m altitude). It is situated in Croatia and Bosnia and Herzegovina (Una-Sana Canton, city Bihać, settlement Doljani and Celije).

It is the highest waterfall in Una National Park, and Lonely Planet described it as "A strong contender for the title of the nation's most impressive waterfall".