Radio Caroline is a European radio station that originally commenced transmissions as an offshore radio station broadcasting from a ship anchored in international waters off the coast of South East England. Originally unlicensed by any government, for the majority of its life it was labelled as a pirate radio station. Founded in 1964 by Ronan O'Rahilly, to circumvent the tight hold the record companies had on the broadcast of popular music in the UK,[1] it was the first such station to broadcast all day using the English language.

The name is now used for various broadcasting ventures with transmissions originating from land, sea, satellite, and the internet.