Solveig Heilo (born December 24, 1981), simply known as Sol Heilo, is a Norwegian composer, artist, musician, music producer, arranger, designer and costume designer. She is mostly known for the band Katzenjammer.

Sol works in different genres, such as folk, rock, pop, bluegrass, classical, blues, soul, country, tribe, klezmer and electronica. Her instruments are drums, trumpet, bass, guitar, melodic percussion, ukulele, domra, banjo, balalaika, zither, harp, flute, accordion, piano, harmonica and mandolin.