D'addario or Daddario is a surname and may refer to:
- Alessandro D'Addario (born 1997), Sammarinese footballer
- Brian and Michael D'Addario, American musicians in The Lemon Twigs
- Emilio Q. Daddario (1918–2010), American politician, father of Richard, grandfather of Alexandra
- Alexandra Daddario (born 1986), American actress and model
- Matthew Daddario (born 1987), American actor, brother of Alexandra
- Gary D'Addario, American retired police commander, television technical advisor and actor
- Lorenzo D'Addario (born 1964), Italian general
- Ray D'Addario (1920–2011), American photographer
- D'Addario, a manufacturer of musical instrument strings and accessories