Carl Gustaf Armfeldt[a] (9 November 1666 – 24 October 1736) was a Swedish officer, general and friherre (baron) who took part in the Great Northern War.

Like other members of his family, Armfelt devoted himself to war and at seventeen years' age joined Nylands kavalleri as a cadet.

During the long war, he distinguished himself in several occasions, especially during the defense of Helsingfors in 1713, but met an overwhelming Russian force and was defeated at the battle of Storkyro in 1714.

In 1717, Armfeldt was promoted to lieutenant general and commanded the Swedish force which on the orders of Charles XII of Sweden was sent into Norway to take Trondheim.

According to the Pernå parish records (cited by Hornborg, 1952) he died at Liljendal in Nyland on 24 October 1736, and was interred at Isnäs on 3 December 1736.