The Tuhinj Valley is a valley in Slovenia linking the Celje Basin with the Ljubljana Basin in an east-west direction along the courses of the Nevljica and Motnišnica rivers.
The western part of the valley was formed by the watershed of the Nevljica, flowing into the Kamnik Bistrica, and the narrower, eastern part by the Motnišnica, a tributary of the Savinja River. Their drainage divide is at the Kozjak Pass at an elevation of 655 m between Cirkuše v Tuhinju and Špitalič. The largest settlements in the valley include Laze v Tuhinju, Šmartno v Tuhinju, and Motnik. The grand number of old settlements points to the fact that the valley was an important thoroughfare in the Middle Ages and later as the passage between Lower Styria and Upper Carniola.
Until the mid-20th century brown coal was mined in the valley near Motnik. Tourism has only recently started to develop with the building of the Snovik Spa.