State Road 23, from Čačak via Zlatibor commonly known as Zlatibor Highway (Serbian: Златиборска магистрала, romanized: Zlatiborska magistrala), is an IB-class road in central and western Serbia, connecting Pojate with Montenegro at Gostun.

[1] Before the new road categorization regulation given in 2013, the route wore the following names: M 5, O 17, M 23.1, M 22 and M 21 (before 2012) / A4, 15, and A6 (after 2012).

By the valid Space Plan of Republic of Serbia the section between Preljina and Požega would be transferred to the new A2 motorway, providing the faster link between Belgrade, Montenegro, and Bosnia and Herzegovina, while the Pojate – Preljina part would link A1 and A2 motorways with the planned route A5.

In order to provide the faster link from Belgrade to Western Serbia and Montenegro and alleviate the dangers of the Ibar Highway, the new A2 motorway is being built on a parallel route Belgrade – Preljina (town in the municipality of Čačak) and on part of the Zlatibor Highway from Preljina to Požega.

[5] Also, the section from Pojate to Preljina would be replaced with motorway A5, by linking the A1 and A2 motorways, allowing the citizens from Southern and Eastern Serbia to reach Western Serbia and surrounding countries Bosnia&Herzegovina and Montenegro.