Jan Julius Lodewijk Duyvendak (28 June 1889 – 9 July 1954) was a Dutch Sinologist and professor of Chinese at Leiden University.

[1] He was co-editor of the renowned sinology journal T'oung Pao with French scholar Paul Pelliot for several decades.

In 1910 Duyvendak moved to Paris where he began more advanced studies in Chinese under Édouard Chavannes and Henri Cordier.

During World War II, Duyvendak worked to protect Jews living in the Netherlands from Nazi forces.

[2] In 1942, Duyvendak published one of the first articles in a Western language on the Crab Nebula supernova as observed by Chinese astronomers in 1054 during the Song dynasty.