Ba () is a village in the municipality of Ljig in central Serbia. According to the 2002 census, the village has a population of 605. It lies below Mount Suvobor.
During World War II, Ba was a stronghold of the Serbian royalist Chetnik movement. Between 25 and 28 January 1944, Chetniks led by Draà ¾a Mihailoviàmet there for discussion in what became known as the Ba Congress. For that reason the village was neglected by post-war Communist authorities.