The MRT Kajang Line, previously known as the MRT Sungai Buloh–Kajang Line, is a Mass Rapid Transit (MRT) line servicing the Klang Valley, Malaysia. It is the second fully automated and driverless rail system in the Klang Valley region after the LRT Kelana Jaya Line. Owned by MRT Corp and operated as part of the Rapid KL system by Rapid Rail, it forms part of the Klang Valley Integrated Transit System. The line is numbered 9 and coloured green on official transit maps.
