Gabriel von Salamanca-Ortenburg (1489 – 12 December 1539) was a Spanish nobleman who was general treasurer and archchancellor of the Habsburg archduke (and future Holy Roman Emperor) Ferdinand I of Austria from 1521 to 1526.
Descending from a wealthy merchant family in Burgos in Castile, Gabriel von Salamanca in 1514 was already chancellor under the Habsburg emperor Maximilian I, who had forged an alliance with King Ferdinand II of Aragon and Queen Isabella I of Castile by marrying his son Philip the Handsome off to their daughter Joanna.
In this period Salamanca made friends with Maximilian's grandson Archduke Ferdinand I, who after the emperor's death in 1519 received the Habsburg hereditary lands of Austria with the duchies of Styria, Carinthia and Carniola (then called "Inner Austria") as well as Tyrol and Further Austria from his elder brother Emperor Charles V in 1521. Gabriel acted as Ferdinand's treasurer and archchancellor; his economic measures however ultimatively failed as his purported self-serving manners met with fierce opposition by the Austrian and Tyrolean aristocracy, who called him an "archarian jew" and "stinking heretic".
In 1523 he was elevated to the rank of an Imperial Freiherr (Baron) and Lord of Ehrenberg Castle in Tyrol as well as of Freyenstein and Karlsbach in Austria. On 10 March 1524 he further received the possessions of the extinct Counts of Ortenburg in Carinthia, which were last held by Count Ulrich II of Celje, together with the Ortenburg comital title, which earned him the enmity of the Bavarian Ortenburg dynasty.
As early as in 1526, he was forced to resign from his positions, and was succeeded by Bishop Bernardo Clesio. Salamanca nevertheless was able to maintain his fiefs; he took his residence at Spittal an der Drau in Carinthia, where he had a luxuriant Renaissance palace built by Italian architects from 1533, today known as Schloss Porcia. Salamanca, however, did not live to see it completed. In compensation for the loss of his offices he had received the Habsburg bailiwick of Ensisheim in Alsace, where he died in 1539.
Gabriel was married twice: to Elisabeth of Eberstein in 1523 (d. about 1330) and to Elisabeth of Baden (1516–1568), daughter of Margrave Ernst of Baden-Durlach in 1533. The marriages produced no children.