Gertrude of Austria (also named Gertrude of Babenberg) (1226 – 24 April 1288) was a member of the House of Babenberg, Duchess of Mödling and later titular Duchess of Austria and Styria. She was the niece of Duke Frederick II of Austria, the last male member of the Babenberg dynasty. She was, according to the Privilegium Minus the first in line to inherit the Duchies of Austria and Styria after the death of childless Frederick, but these claims were disputed by her aunt Margaret.
Gertrude was the only child of Henry of Austria, Duke of Mödling, by his wife Agnes, daughter of Hermann I, Landgrave of Thuringia. Henry, in turn, was the second son of Duke Leopold VI of Austria. In 1216, after the death of his older brother Leopold, Henry became his father's heir.
Henry died on 26 September 1228, only twenty years old and without male issue. Two years later, on 28 July 1230, Henry's father Duke Leopold VI also died and was succeeded by Frederick II, Leopold's third son. Because Babenberg Austria was inheritable by females according to the provisions of Privilegium Minus, Gertrude disputed Frederick's ascension, claiming Austria as her inheritance as the only child of Leopold VI's eldest son. Even so, Gertrude's claim was eventually bypassed in her uncle's favor.
Despite this negative turn of events, Gertrude inherited her father's Duchy of Mödling and was placed under the guardianship of her uncle, Frederick II, who, after two unhappy marriages, remained childless. This made Gertrude the primogenitural heiress of the entire Babenberg line of Dukes of Austria and Styria.
Complicating Frederick II's hold over Austria was his long-standing quarrel with Frederick II, Holy Roman Emperor, during which he was placed under an imperial ban. In 1245, in a spectacular change of imperial politics, Frederick II of Austria became one of the emperor's most important allies when negotiations regarding the elevation of Vienna to a bishopric and of Austria (including Styria) to a Kingdom were initiated. One condition effecting a positive outcome was that the 19-year-old Duke's niece, Gertrude, would marry the 51-year-old Emperor who was a widower three times over. Though desirous of the union, Wenceslaus I of Bohemia nevertheless voiced his concerns given a preexisting agreement that Gertrude marry his eldest son and heir Vladislaus. Gertrude herself refused the marriage with the aged Emperor, citing his recent excommunication by the Pope. Other sources claim that she was in love with Vladislaus. After sending an army to Austria in order to pressure Duke Frederick II into agreeing to the union of Gertrude and Vladislaus, the two parties came to terms early in June 1245 in Verona. The rapid rise of Duke Frederick's political ambitions proved short-lived.