John Harlan Willis (June 10, 1921 – February 28, 1945) was a United States Navy hospital corpsman who was killed in action during World War II while serving with a Marine Corps rifle company.

He was posthumously awarded the nation's highest military decoration for valor, the Medal of Honor, for heroic actions "above and beyond the call of duty" on February 28, 1945, during the Battle of Iwo Jima.

He participated in the Battle of Iwo Jima as a rifle company platoon corpsman and, on February 28, while aiding fallen Marines during a fierce action near Japanese-held Hill 362, he was wounded by shrapnel and ordered back to the battle-aid station.

Constantly imperiled by artillery and mortar fire from strong and mutually supporting pillboxes and caves studding Hill 362 in the enemy's cross-island defenses, Willis resolutely administered first aid to the many marines wounded during the furious close-in fighting until he himself was struck by shrapnel and was ordered back to the battle-aid station.

Without waiting for official medical release, he quickly returned to his company and, during a savage hand-to-hand enemy counterattack, daringly advanced to the extreme frontlines under mortar and sniper fire to aid a marine lying wounded in a shellhole.

Completely unmindful of his own danger as the Japanese intensified their attack, Willis calmly continued to administer blood plasma to his patient, promptly returning the first hostile grenade which landed in the shell-hole while he was working and hurling back 7 more in quick succession before the ninth exploded in his hand and instantly killed him.