Denmark was represented at the Eurovision Song Contest 1978 with the song "Boom Boom", written and performed by the group Mabel.

The Danish participating broadcaster, Danmarks Radio (DR), organised the Dansk Melodi Grand Prix 1978 in order to select its entry for the contest.

Danmarks Radio (DR) held the Dansk Melodi Grand Prix 1978 on 25 February at the Tivoli Concert Hall in Copenhagen, hosted by Jørgen de Mylius.

Six songs took part with the winner being decided by votes from eight regional juries.

On the night of the final Mabel performed 16th in the running order, following Greece's "Charlie Chaplin" by Tania Tsanaklidou and preceding Luxembourg's "Parlez-vous français ?"