John Arthur Ljunggren (September 9, 1919 – January 13, 2000) was a Swedish athlete who competed mainly in the 50 kilometer walk.
Ljunggren first appeared in the Olympics in the 1948 Games held in postwar London. He finished first in the 50 kilometre walk, winning the gold medal.
His next Olympic success came in the 1956 Summer Olympics held in Melbourne, Australia in the 50 kilometre walk where he won the bronze medal.
He returned four years later in the 1960 Summer Olympics held in Rome, Italy where he was unable to match his 1948 performance but he improved his 1952 position in the 50 kilometre walk to silver medal behind Great Britain’s Don Thompson. In the European championship he won the gold medal in the 1946 and the silver medal in the 1950.