Violet Line may refer to: Violet Line (1914), a boundary between the Ottoman Empire and the British Empire in Arabia Violet line piranha, a species of fish Violet Line (Delhi Metro), a line of the rapid transit system in Delhi, India Violet Line (Ahmedabad Metro), a line of the rapid transit system in Ahmedabad, India Line 6 (Riyadh Metro), a line of the rapid transit system in Riyadh, Saudi Arabia. (Also sometimes referred as Purple Line) Line 16 (São Paulo Metro), a proposed rapid transit line in São Paulo, Brazil