Siv Margaretha Pettersson (3 March 1955 – 12 January 1975) was a Swedish singer, best known for her Christmas song "Låt mig få tända ett ljus (Schlafe, mein Prinzchen, schlaf' ein)".
Petterson was born in Saint Matthew Parish, Stockholm.
She had a major 1972–1973 Christmas hit with "Låt mig få tända ett ljus" and a minor 1974 success with Evert Taube's "Så länge skutan kan gå".
She died in a road accident in Årjäng, Värmland County, in January 1975, aged 19.