Cardy is a surname. Notable people with the surname include:
Alan Cardy, representative of Australia in rugby union
Dominic Cardy (born 1970), English born Canadian politician
John Cardy, British theoretical physicist
Julien Cardy (born 1981), midfielder in the French Football League
Nick Cardy (1920–2013), American comic book artist
Peter Cardy, British activist
Graeme Cardy, Newcastle United fan, World's Worst Comedian