Bryan Malcolm Gaensler (born 1973) is an Australian astronomer based at the University of California, Santa Cruz.

In 2014, he was appointed as Director of the Dunlap Institute for Astronomy & Astrophysics at the University of Toronto, after James R. Graham's departure.

[8] In June 2014, Gaensler announced that he would be leaving CAASTRO and taking up a position as director of the Dunlap Institute for Astronomy and Astrophysics at The University of Toronto[9] commencing in January 2015.

[13] In 2004, Gaensler used the Chandra X-ray Observatory to make the first detailed study of the behavior of high-energy particles around a fast moving pulsar.

[16] Also in 2005, he reported puzzling new observations of the Large Magellanic Cloud, showing that powerful but unknown forces were at work in maintaining this galaxy's magnetic field.