The Commemorative Medal of the Reign of King Leopold II (French: Médaille Commémorative du Règne du Roi Léopold II, Dutch: Herinneringsmedaille aan de Regeerperiode van Leopold II) was a Belgian civilian and later military and police forces medal originally established on 21 July 1905 by royal decree to commemorate the 40th year of the reign of King Leopold II.

[2] The medal was once again reissued for a third time in 1952, again slightly modified, to members and veterans of the Force Publique who also had a minimum of one year's good and faithful service between 1 July 1885 and 18 December 1909.

Its obverse bore the relief image of a cross pattée with a central medallion bearing the left profile of King Leopold II; the cross was superimposed over a wreath of laurel and oak branches along the medal's circumference.

The reverse bore the same basic design except for the king's profile which was replaced by the years inscribed in relief on two rows "1865 1905" for the initial type (1905) awarded to civil servants,[1] "1865 1909" for the second type (1951) awarded to the military[2] and "1885 1909" to the Force Publique (1952).

[1] The individuals listed below were awarded the Commemorative Medal of the Reign of King Leopold II:[4]