Alexandru Cantacuzino-Deleanu or Alexandros Kantakouzinos (Greek: Αλέξανδρος Καντακουζηνός: c. 1787 in Iași, Moldavia – 1841 in Athens, Greece) was a Phanariote Romanian-Greek magnate and politician.
The matrimony made Alexandros a married-in-member of the influential Rozumovski clan – his wife's cousins, who at this time held such eminent positions as Ambassador to the Austrian court in Vienna, and Minister of Education in St. Petersburg.
His brother, Grigore Cantacuzino-Deleanu served in the Imperial Russian Army and rose to the rank of colonel, before being killed in the Battle of Borodino in 1812 against Napoleon's invasion of Russia.
In 1812, after another Russo-Turkish war, Eastern Moldavia was annexed to the Russian Empire, and Alexandros' father, his mother and his siblings and their families returned to their ancestral home.
Kantakouzinos participated in the capture of Monemvasia and the Siege of Tripolitsa, but in 1822 he fell out with Dimitrios Ypsilantis and joined the camp of his rival, the Phanariote Alexandros Mavrokordatos.