Aluminum monoxide (AlO) was identified in a 2009 paper by Tenenbaum & Ziurys based on observations in VY Canis Majoris, an oxygen-rich supergiant that has recently been found to be a surprisingly rich source of molecules. The observations were made with the 10m Submillimeter Telescope at the Arizona Radio Observatory on Mt. Graham. Other small molecules containing Al that have been identified in various sources include AlCl & AlF (1987), AlNC (2002), and AlOH (2010).

Diatomic AlO bears little resemblance to the extended form of aluminum oxide (Al₂O₃) of which very hard minerals such as corundum are composed.