Jan Leonard Groth (25 February 1946 – 27 August 2014) was a Norwegian musician.

Groth was born in the borough of Greåker in Sarpsborg, Norway.

He first made his name in the early 1970s as a member of the progressive rock band Aunt Mary, where he was lead singer and keyboardist.

Barratts salmebok to mark the 100th anniversary of the Pentecostal Church in Norway.

Groth died on 27 August 2014, aged 68, from cancer.