Vlașca County is a former first-order administrative division of the Kingdom of Romania, in southern Muntenia, located between Bucharest and the Danube, which is now mostly the county of Giurgiu. The county seat was Giurgiu.
The county was located in the southern part of Greater Romania, in the southern part of the historical region of Muntenia. The county was bordered on the west by Teleorman County, on the northwest by Argeș County, on the north by Dâmboviţa County, on the east by Ilfov County, and to the south by the Kingdom of Bulgaria. Its surface coincides in large part with that of the present Giurgiu County, but there are small parts of it that are included in today's Teleorman County.