Alexandru Ioan Cuza, or Alexandru Ioan I, also anglicised as Alexander John Cuza; 20 March 1820 – 15 May 1873) is Prince of Moldavia, Prince of Wallachia, and later Domnitor (ruler) of the Romanian Principalities.

He is a prominent figure of the Revolution of 1848 in Moldavia.

He initiates a series of reforms that contribute to the modernization of Romanian society and of state structures.