Alessandro Barnabò (2 March 1801 – 24 February 1874) was an Italian Catholic Cardinal and Prefect of the Congregation Propaganda Fide.

Between his ordination and 1856 he held a number of official positions including Privy chamberlain supernumerary, Consultor to the Propaganda Fide, Keeper of the Seals of the Apostolic Penitentiary and served as a domestic prelate to the Pope.

[4] As Prefect, Barnabò was responsible for arranging a meeting between Pope Pius IX and Isaac Hecker.

Hecker had been expelled from his Redemptorist order but Barnabò recognised his valuable missionary work and helped him appeal to the Pope who overturned the expulsion.

For a year (1868–1869), as was customary for the office, Barnabò was appointed Camerlengo of the Sacred College of Cardinals.