Lagadec or Lagadeg is a surname, and may refer to:
Lagadec derives from the Breton adjectif lagadeg which means "who has good eyes, possibly big eyes".
(born 1948), French economics researcher - Breton writer Jean-Louis Lagadec (1933–2012), French footballer or Lagadeuc - Breton priest (1950–2018), French journalist and Breton activist (1962–1989), French nurse and daughter of Jean-Baptiste Lagadec