Freiherr Arvid Axel Mardefelt (around 1655 – Jakin, Poland May 18, 1708) was a Swedish Infantry General from the 18th century and a familiar of Charles XII of Sweden.
Mardefelt was the son of Fieldmarshal Conrad Mardefelt. In 1702 during the Great Northern War, he was in charge of the operations of the Swedish Army in Western Poland and in 1704 he conquered Poznań. In 1706 he distinguished himself in the Battle of Fraustadt.
On October 29 1706, he and his army of 5,000 Swedish and 10,000 Polish Soldiers faced near Kalisz an army of 35,000 Russian, Saxon and Polish troops under August the Strong, and were defeated. His Polish cavalry under Stanisław Leszczyński was routed. Mardefelt together with 100 officers, including Polish Magnates, were made prisoners of War.
After his release in 1707, Mardefelt died of Gout.