Y6 was a series of diesel railcars operated by Statens Järnvägar (SJ) of Sweden. 378 motor cars and 321 trailers were delivered between 1953-61 by Hägglund & Söner, , Kalmar Mekaniska Verkstad and . They were used throughout the unelectrified Swedish rail network during the 1950s to the 1980s. The electrical counterpart of the unit was the X16 and X17. In addition to SJ, five units were sold to in 1954.