The MRT Putrajaya Line, is the second Mass Rapid Transit (MRT) line in Klang Valley, Malaysia, and the third fully automated and driverless rail system in the country. It was previously known as the MRT Sungai Buloh–Serdang–Putrajaya Line. The line stretches from Kwasa Damansara to Putrajaya and runs through densely populated areas such as Sri Damansara, Kepong, Batu, Jalan Ipoh, Sentul, Kampung Baru, Jalan Tun Razak, KLCC, Tun Razak Exchange, Kuchai Lama, Seri Kembangan and Cyberjaya.

The Klang Valley Mass Rapid Transit project is a planned three-line mass rapid transit (MRT) system in the Klang Valley, an urban conurbation in Malaysia which includes the capital city of Kuala Lumpur. The MRT lines, when completed, would be operated as components of the Klang Valley Integrated Transit System.