Harm Jan Habing (born 31 October 1937 in Tubbergen, Overijssel, Netherlands) is a Dutch astronomer and emeritus professor of astrophysics at Leiden University.

He obtained his doctorate in Groningen in 1968 with a thesis entitled Studies of physical conditions in HI regions supervised by Stuart Robert Pottasch and Hendrik Christoffel van de Hulst.

In 1971 Habing was appointed lecturer in astrophysics at Leiden University and in 1979 he was promoted to full professor.

Ewine van Dishoeck and Xander Tielens were among Harm Habing's PhD students.

[1] Habing is known for his 1968 research into the far-ultraviolet (between 91 and 240 nanometers) radiation field in the space between the stars.