The R503 is a Regional Route in North West, South Africa that connects Mahikeng with Klerksdorp via Lichtenburg and Coligny.

It goes south-east for 62 kilometres, forming the southern border of the Mafikeng Game Reserve, bypassing Itsoseng, to the town of Lichtenburg, where it enters in an easterly direction and meets the R505 route.

[1] The R505 joins the R503 and they are one road eastwards into the town centre as Swart Street, then southwards as Nelson Mandela Drive, to meet the R52 route at the junction with Gerrit Maritz Street.

At the next junction, the R505 becomes its own road southwards while the R503 turns to the south-east as Kalkweg Way.

From Hartbeesfontein, the R503 goes south-east for 20 kilometres to enter the city of Klerksdorp and reach its terminus at a T-junction with the N12 national route in the suburb of Freemanville (west of the town centre; north of Jouberton).