Zagorje ob Savi (pronounced [zaˈɡoːɾjɛ ɔp ˈsaːʋi] ⓘ; German: Sagor,[2] Seger an der Sau[3]) is a town in the Central Sava Valley in central Slovenia.

The entire municipality is now included in the Central Sava Statistical Region.

Zagorje ob Savi was attested in written sources as Zagorie in 1296, Zagoͤr in 1311, Sager in 1362, Sagor in 1391, and Seger in 1419, among other spellings.

[9] In 1755 deposits of coal were discovered in the area and the town's economic development began.

The parish church in the settlement is dedicated to Saints Peter and Paul and belongs to the Roman Catholic Archdiocese of Ljubljana.