The Yellow Line is a metro rail line of the Delhi Metro, a rapid transit system in Delhi, India. It consists of 37 stations from Samaypur Badli in Delhi to Millennium City Centre in the neighbouring city of Gurgaon in Haryana. The 49.02 kilometers (30.46 mi) line is mostly underground and laid under one of the most congested parts of Delhi. The Yellow Line is the second line of Delhi Metro to become operational after the Red Line.

The Delhi Metro is a mass rapid transit system which serves Delhi and its adjoining satellite cities, such as Ghaziabad, Faridabad, Gurugram, Noida and Bahadurgarh, in the National Capital Region of India. The system consists of 10 colour-coded lines serving 256 stations, with a total length of 350.42 kilometres (217.74 mi). It is India's largest and busiest metro rail system and the second-oldest, after the Kolkata Metro. The metro has a mix of underground, at-grade, and elevated stations using broad-gauge and standard-gauge tracks. The metro makes over 4,300 trips daily.