Margareta von Ascheberg as married Barnekow (1671–1753), was a Swedish land owner, noble and acting regiment colonel during the Great Northern War.
Daughter of Field Marshal Rutger von Ascheberg and married in 1691 to count and military Kjell Christopher Barnekow (d. 1700). As a widow, she had the obligation to perform his task of a colonel regarding the organisation of his regiment, when it was called to serve in the Great Northern war in 1700. She equipped the regiment, appointed the officers of the regiment and sat at the inspection office of the regiment when it was sent to war from Kristianstad. During the war, she took care of the continued equipment and affairs of the regiment, exchanged letters with Charles XII of Sweden about its appointments and promotions. She was called "Coloneless"; "Madame Colonel". She was also an active and successful businessperson as a landowner, who expanded and developed her vast estates; she founded schools and hospitals and gave anonymous donations to the poor.