Károly Hadaly (1743, Kolárovo – 1834, Budapest) was a Hungarian mathematician. He studied at the university of Trnava, where he earned doctorates in philosophy and law. He was a professor of mathematics in Nagyszombat (currently Trnava), in Győr, in Pécs, in Pozsony (currently Bratislava) and in Budapest. From 1810 to 1831 he taught mathematics and physics in Institutum geometricum.