Alpha-neoagaro-oligosaccharide hydrolase (, alpha-neoagarooligosaccharide hydrolase, alpha-NAOS hydrolase) is an enzyme with systematic name alpha-neoagaro-oligosaccharide 3-glycohydrolase. This enzyme catalyses the following chemical reaction
When neoagarohexaose is used as a substrate, the oligosaccharide is cleaved at the non-reducing end to produce 3,6-anhydro-L-galactose and agaropentaose, which is further hydrolysed to agarobiose and agarotriose.