Budacu de Jos (; ) is a commune in Bistrița-Năsăud County, Transylvania, Romania. It is composed of five villages: Budacu de Jos, Buduș (Alsóbudak;Budesdorf), Jelna (Kiszsolna; Senndorf), Monariu (Malomárka; Minarken), and Simionești (Simontelke; Seimersdorf).
The commune is situated on the Transylvanian Plateau, at the foot of the Călimani Mountains. The river Budac (a tributary of the Șieu) flows through the commune.
Located in the Nösnerland historic region of Transylvania, Budacu de Jos lies in the south-central part of Bistrița-Năsăud County, south of the county seat, Bistrița. County road DJ172G connects the component villages of the commune, while road DJ173C leads to the city of Bistrița.
At the 2011 census, 78.97% of inhabitants were Romanians and 17.93% Roma.