The M21 road is a long metropolitan route in the City of Tshwane in Gauteng, South Africa.

It continues north to meet the R566 route at De Wildt before entering the township of Ga-Rankuwa in Gauteng as Kware Street.

[5] It heads north-north-east through the centre of Ga-Rankuwa to pass through Hebron (where it meets the north-western terminus of the M20 route) as the Molefe Makinta Highway (formerly Lucas Mangope Highway[6]) before passing through Mabopane.

In the town of Winterveld, the M21 bends to the east-north-east and meets the M39 route before passing through the northern part of Soshanguve, where it meets the M35 route.

[5] After Soshanguve, the M21 turns northwards into Nuwe Eersterus, then eastwards at the Mogogelo Road junction, to reach the township of Hammanskraal, where it makes a right turn and becomes Herry Gwala Avenue before crossing the Apies River and reaching its end at a junction with the R101 route (Old Warmbaths Road).