The EMD SD9 is a model of diesel locomotive built by General Motors Electro-Motive Division between January 1954 and June 1959.

Many SD9s both high and short hood can still be found in service today on shortline railroads and industrial operators.

[citation needed] The SD9 was the second model of EMD's SD (special duty) line of locomotives, following the SD7.

[2] SD9s can be distinguished from the similar looking SD7s by observing the position of the classification lights on the ends of the locomotive, above the number board.

This locomotive had its weight reduced for service on lighter tracks with modifications such as a smaller fuel tank.