Fürst von Dietrichstein zu Nikolsburg; 4 August 1813 in Coburg – 14 February 1871) was an Austrian general, diplomat and politician, including two years as Minister of Foreign Affairs (1864–66) and one month's service as Minister-President of Austria.

By birth, he was member of the House of Mensdorff-Pouilly, an old Lotharingian noble family, domiciled in Austria since the second half of the 18th century.

His maternal grandparents were Francis, Duke of Saxe-Coburg-Saalfeld and his second wife, Countess Augusta Reuss of Ebersdorf.

Mensdorff-Pouilly's policies during his tenure as Foreign Minister for Emperor Franz Joseph were often largely a continuation of the conservative traditionalism of Count Johann von Rechberg und Rothenlöwen, his predecessor.

[1] After Austria's defeat in the Austro-Prussian War of 1866, Mensdorff-Pouilly resigned his functions in November of that year.