Maria of Brabant (c. 1190 – May/June 1260), a member of the House of Reginar, was Holy Roman Empress from 1214 until 1215 as the second and last wife of the Welf emperor Otto IV.

Duke Henry of Brabant now hastened to reconcile with the Welf ruler, renewing the prospect of his daughter marrying Otto, but once again, this did not happen.

Soon after his coronation, Otto IV steered into conflict with the Pope over the Kingdom of Sicily, then ruled by the young Hohenstaufen prince Frederick II, nephew of the late Philip of Swabia.

One year after this, Otto demonstratively married Beatrice of Swabia, daughter of his original rival the late King Philip, and paternal first cousin to Frederick.

Crowned king by Archbishop Siegfried II of Mainz in December 1212, Frederick's rise continued unabated and Otto was under increasing pressure.

Her husband's rule came to an end, when Frederick forged an alliance with King Philip II of France and provoked Otto to enter into the Anglo-French War.

Pope Innocent III, who had previously crowned Otto, acknowledged Frederick's rule as emperor-to-be during the Fourth Council of the Lateran in November.