Josef Kjellgren, (13 November 1907 – 8 April 1948) was a Swedish writer and playwright.

Kjellgren was a proletarian writer and a member of the influential modernist literary group Fem unga ('Five Young Ones') who published an anthology of the same name in 1929.

Kjellgren's main theme was proletarian internationalism and solidarity within the working class.

[1] Kjellgren is best known for his later novels, including Människor kring en bro ('People Around a Bridge', 1935), about the building of Västerbron in Stockholm, and Smaragden ('The Emerald', 1939).

Kjellgren also wrote a play, Okänd svensk soldat ('Unknown Swedish Soldier', 1938), which was the basis for the 1948 movie Främmande hamn ('Foreign Harbour'), directed by Hampe Faustman.