Kyustendil is a town in the far west of Bulgaria, the capital of the Kyustendil Province, a former bishopric and present Latin Catholic titular see.

The town is situated in the southern part of the Kyustendil Valley, near the borders of Serbia and the Republic of Macedonia; 90 km southwest of Sofia, 130 km northeast of Skopje and 243 km north of Thessaloniki. The population is 44,532.