Alexander Gemignani (born July 3, 1979) is a Broadway performer. Alexander was raised in Tenafly, New Jersey and is a graduate of the University of Michigan's Musical Theater Department. He is the son of Broadway musical director Paul Gemignani.

He appeared as John Hinckley in the Roundabout's 2004 Broadway mounting of Stephen Sondheim's Assassins. Gemignani returned to Broadway in late 2005 as the Beadle in the revival of Sweeney Todd. He has appeared in concert versions of both South Pacific (with Reba McEntire and Brian Stokes Mitchell at Carnegie Hall in June, 2005) and Passion (with Patti LuPone, Michael Cerveris, and Audra McDonald at The Rose Theater in March, 2005). Both concerts were taped for PBS Great Performances. In addition, Gemignani participated in a memorable performance of Opening Doors from Sondheim's Merrily We Roll Along at Symphony Space's March, 2005 Wall to Wall Sondheim event celebrating Sondheim's 75th birthday. Gemignani recently starred as Jean Valjean in the Broadway revival of Les Misérables, which opened November 9, 2006, at the Broadhurst Theatre.

In late 2007, Alex appeared on the national tour of John Doyle's Sweeney Todd. He appeared in the title role opposite Judy Kaye at the Toronto and Columbus, Ohio, stops of the tour. After the Columbus leg of the tour, Alex left the show to return to New York City, where he appeared in 2008's Broadway revival of Sunday in the Park With George.