Cadwallader Davis Blayney, 12th Baron Blayney (19 December 1802 – 18 January 1874), styled The Honourable from birth until 1834, was an Irish nobleman and politician. Born in Dover Street in London, he was the son of Andrew Blayney, 11th Baron Blayney and his wife Marbella, the eldest daughter of James Alexander, 1st Earl of Caledon. He is buried in Kensal Green Cemetery north-west of the main chapel.