Antti Johannes Rantamaa (26 November 1904 Merikarvia, Finland – 17 August 1987 Switzerland) was a Finnish priest, member of the Finnish Parliament, figure of the Winter War, and author. He was one of the heads of the Evangelical Lutheran Church of Finland. Rantamaa is famous as the chaplain in the Finnish postcard depicting Christmas devotions said to have taken place in 1939 under enemy fire, causing it to cease.