William Adelbert Foster (February 17, 1915 – May 2, 1945) was a United States Marine who received the Medal of Honor for his "conspicuous gallantry and intrepidity at the risk of his life above and beyond the call of duty" during World War II during the Battle of Okinawa in 1945.

In late September 1944, after intensive combat training at Camp Pendleton, he embarked for overseas duty on board the USS General C. G. Morton bound for the Russell Islands in the Solomon group.

In combat for the first time at Okinawa, PFC Foster performed an act of heroism on May 2, 1945, which earned for him the nation's highest military decoration: the Medal of Honor.

When a Japanese grenade landed beyond reach in their foxhole, Private First Class Foster, with complete disregard for his personal safety, dove on it and absorbed its full explosion with his own body, thus protecting the other Marine from serious injury.

Foster's awards include: The President of the United States takes pride in presenting the MEDAL OF HONOR posthumously to for service as set forth in the following CITATION: