We present a catalogue of high velocity clouds (HVCs) from the second release of the Galactic All Sky Survey in neutral hydrogen. Our catalogue resolves for the first time the velocity width distribution of southern-sky HVCs, revealing a median cloud line-width of 19 km/s, and also probes further into the boundary between gas of Galactic and extragalactic origin than typical catalogues of HVCs. Our data was taken with the Parkes radio telescope and has been stray-radiation corrected, consisting of 57 mK sensitivity, 1 km/s velocity resolution and 16' angular resolution. The GASS catalogue of HVCs improves on previous studies with its unprecedented combination of spectral and angular resolution in an all-southern-sky survey, allowing us to investigate how the dynamic and interacting population of anomalous velocity clouds in the Milky Way can offer insights into HI gas at the bridge between the disk and the halo of our Galaxy.