The Södermanland Regiment, designated P 10 or P 3 and P 10/Fo 43, was an armored regiment of the Swedish Army with its roots in the 17th century, and was located in Strängnäs. The regiment was deactivated in 2004 and its assets were funneled into other parts of the military. Its life company was transferred to the Södermanland Group of the Home Guard, making the Södermanland Group the only Home Guard unit with such a company.

Södermanland Regiment, designation I 10, was a Swedish Army infantry regiment that operated 1634–1942 and 1957–1963. The unit was based in the Strängnäs Garrison in Strängnäs, Södermanland, Sweden. In 1963 the regiment was transferred to the Swedish Armoured Troops under the name of Södermanland Regiment.