Wagenaar is a Dutch surname shared by the following people:
Bernard Wagenaar, American composer
Diderik Wagenaar, a composer and musical theorist
Jan Wagenaar (waterpolo), a water polo player
Jan Wagenaar, an 18th-century Dutch historian
Johan Wagenaar, a composer and organist
Josh Wagenaar, a footballer
Rene Wagenaar (1954 -2007), Dutch Professor of Information and Communication Technology
Willem Albert Wagenaar, a psychologist