Leif Welding-Olsen (15 August 1895 – 8 April 1940) was the commander of the Royal Norwegian Navy patrol boat HNoMS Pol III.

[1] On 8 April 1940, Leif Welding-Olsen raised the alarm as the German navy ships moved past the guard lines in outer Oslofjord.

Norway had been attacked at 22:05 hrs that evening as German ships passed the Norwegian territorial borders.

Leif Welding-Olsen, weakened by blood loss, let go from the boat and drowned, becoming the first casualty in the war between Norway and Nazi Germany.

His last words were reportedly: "Bry dere ikke om meg gutter, jeg er ferdig likevel.