Margaret's elder sister, Joan III, inherited the counties of Artois and Burgundy when their mother died in 1330.

He and Margaret had one son, Count Louis II of Flanders,[2] who succeeded his father and for whom she acted as a regent in the beginning of his reign.

Reputedly, Margaret, vexed at the ill will of the count her son, had one day said to him, as she tore open her dress before his eyes, "Since you will not yield to your mother's wishes, I will cut off these breasts which gave suck to you, to you and to no other, and will throw them to the dogs to devour."

A French army (and Philip the Bold) came to help them regain Flanders, and the revolting Flemings were decisively defeated at the Battle of Roosebeke, the year in which Margaret died.

However, the citizens of Ghent continued to resist with English aid, and it was left to her granddaughter and grandson-in-law to subdue the town.