Marguerite d'Oingt was a member of a powerful family from the area around Lyon. She entered a women's Carthusian community at Poleteins, and by 1288 she was its prioress. The Carthusian Order, founded 200 years earlier at the La Grande Chartreuse in the Alps (hence the name given to each foundation: "charterhouse"), combined the hermit's life with that of the monk. The few women's charterhouses followed the same austere life as did the men's.

By 1288 Marguerite had begun to write a Latin set of meditations, Pagina Meditationum. Later she wrote in Franco-Provencal, which suggests a readership that perhaps included the laity, or at least an audience less skilled in Latin than Marguerite. By 1294, she had completed her most popular work, the vernacular Speculum (Mirror); a Carthusian prior took this work to the General Chapter at the Grande Chartreuse, where it was approved for copying and distribution. References in her letters suggest that she wrote several works that have not survived; her last extant work was written sometime after 1303, Vie de sainte Beatrice d'Ornacieux, about a nun at another charterhouse, whom the Carthusians believed to be a saint.

In most of her extant writing, Marguerite's goal is to teach her readers how to meditate; to do this she most frequently uses images of reading and writing, of manuscripts and their illumination, and she presents these images in a simple and direct style.

Blessed Marguerite died around the year 1310.