Gustaf Olof (Olle) Hjortzberg (14 November 1872 – 8 March 1959) was a Swedish painter and illustrator.

In 1886, he moved to Stockholm where he became acquainted with the architect and illustrator Agi Lindegren who introduced him to ornamental work.

In 1902, he visited London before returning to Italy where he stayed for a time in Rome studying the old masters before travelling to Ravenna to see the Byzantine art.

In 1913, he decorated Uppenbarelsekyrkan in Saltsjöbaden with strongly coloured Christian figures in a style inspired by Byzantine and Assyrian art.

[1] Hjortzberg was also active as an illustrator, contributing to the Gustav V Bible (published 1925), creating a poster for the Stockholm Olympic Games (1912) and designing commemorative stamps.