The Light Rail Transit Line 1, commonly referred to as LRT Line 1 or LRT-1, is a light rapid transit system line in Metro Manila, Philippines, operated by Light Rail Manila Corporation (LRMC) and owned by the Light Rail Transit Authority (LRTA) as part of the Manila Light Rail Transit System. Originally referred to as Metrorail and the Yellow Line, LRT Line 1 was reclassified to be the Green Line in 2012. It travels in a general north–south direction from Baclaran to Monumento, and then east–west from Monumento to Fernando Poe Jr. Currently, the line consists of 20 stations and runs on 19.65 kilometers of fully elevated route. Although it has the characteristics of light rail, such as with the type of rolling stock used, it is more akin to a rapid transit system owing to its total grade separation and high passenger throughput.

The Manila Light Rail Transit System, commonly known as the LRT, is an urban rail transit system that primarily serves Metro Manila, Philippines. Although categorized as a light rail system because it originally used light rail vehicles, it presently has characteristics of a rapid transit system, such as high passenger throughput, exclusive right-of-way, and later use of full metro rolling stock. The LRT is jointly-operated by the Light Rail Transit Authority (LRTA), a government corporation attached to the Department of Transportation (DOTr), and the Light Rail Manila Corporation (LRMC). Along with the Manila Metro Rail Transit System and the Metro Commuter Line of the Philippine National Railways, the system makes up Metro Manila's rail infrastructure.