Countess Teresa of Portugal, a.k.a. Princess Teresa of León (1080–November 11, 1130), was an illegitimate daughter of King Alfonso VI of Castile and León and Jimena Muñoz, daughter of the Count of Asturias. In 1094, she married Henry of Burgundy while on crusade in Iberia against the Moors. The County of Portugal was part of her dowry, establishing Henry as Count of Portugal.

At first, Henry was a vassal of his father-in-law, but when Alfonso VI died in 1109, leaving everything to his daughter Urraca of Castile, Henry invaded León, hoping to add it to his lands. When he died in 1112, Teresa was left to deal with the mess. Although their son Afonso I of Portugal (a.k.a. Afonso Henriques) succeeded to the countship, he was young and was therefore placed under his mother's tutelage. She took on the responsibility as regent and governed her land that had only recently been reconquered from the Moors and only as far as the Mondego River.

In 1116, in an effort to expand the land that would descend to her son (who later became the first King of Portugal), Teresa fought her half-sister and queen, Urraca. They fought again in 1120. In 1121, she was besieged and captured at Lanhoso. A negotiated peace was coordinated with aid from the Archbishops of Santiago de Compostela and Braga. The terms included that Teresa would go free and hold the county of Portugal as a fief of León.

Teresa tried to retain the rule of the county even after her son's majority. Over the course of five years, she lavished wealth and titles on her lover, Fernando Peres, Count of Trava. These actions estranged her other son (who was the Archbishop of Braga) and the nobles, who were mostly foreign crusaders. By 1128, her sons and the nobles were fed up. Afonso was named sole ruler. He defeated Teresa's troops near Guimarães and took her prisoner. She was deposed and exiled (some sources say to a convent, other say with Fernando Peres). Teresa died in 1130.