The Medalje vir Troue Diens (Medal for Loyal Service) is a South African military medal. It was instituted with effect from 27 April 2003, and is awarded to members of the South African National Defence Force who complete ten years qualifying service and whose character and conduct have been irreproachable. Clasps are added after further periods of ten years service.
The medal is silver-nickel, and has a scalloped edge. The obverse displays the South African coat of arms, and the reverse bears the words "Vir Troue Diens". This design is an updated version of a design which has been used for military long service medals since 1952.
The ribbon is green edged in red and white (on the left) and blue and white (on the right). The Emblem for Reserve Force Service is worn on the ribbon by those who have received it.