Oriovac is a village and a municipality in Brod-Posavina County, Croatia.
Until 1918, Oriovac (named Oriowacz before 1850) was part of the Austrian monarchy (Kingdom of Croatia-Slavonia after the compromise of 1867), in the Slavonian Military Frontier, Gradiskaner Regiment NðVIII before its dissolution in 1881.
In 2021, the municipality had 4,770 residents in the following 10 settlements: