Maria Theresia Franziska Josepha Johanna Benedikta (German) was a member of the Tuscan branch of the House of Habsburg-Lorraine, and an Archduchess of Austria and Princess of Bohemia, Hungary and Tuscany by birth.

During the reign of her spouse, Maria Theresa did not involve herself in state affairs, reportedly devoting her time solely to her family and religion.

A convinced Catholic, a fully converted fervent Italian Nationalist, and a new brand conservative who believed in checks and balances on royal power, she had a great influence on her eldest son.

In fact, her parents had the same four grandparents, so they were double cousins when they married: this practice of alliances between cousins was still common at that time, given that the families (and notably, including the parents and grandparents of Maria Theresa) had a lot of children, and this avoided dividing the benefit of heirs too much through alliances and their descendants, and the multiplication of nobility titles to satisfy the various claims by descendants.

Her paternal grandfather, Leopold II, Holy Roman Emperor, was the brother of her maternal grandmother, Maria Carolina of Austria.

Matching that combination, her paternal grandmother, Maria Luisa of Spain, was the sister of her maternal grandfather, Ferdinand I of the Two Sicilies.