'''Castonguay''' is a surname. Notable people with this surname include:
*Alexandre Castonguay (born 1968), Canadian media artist *Antoine Castonguay (1881–1959), Canadian politician *Charles Castonguay (born 1940), Canadian mathematician *Claude Castonguay (1929–2020), Canadian politician *Émilie Castonguay, Canadian sports agent *Éric Castonguay (born 1987), Canadian ice hockey player *Jeannot Castonguay (born 1944), Canadian politician *Marilyn Castonguay, Canadian actress *Mike Castonguay, American musician *Roch Castonguay, Canadian film and television actor
==See also== {{srt|surname}}
{{surname|Castonguay}}