In enzymology, a xyloglucan-specific endo-beta-1,4-glucanase (EC 3.2.1.151) is an enzyme that catalyzes the chemical reaction: xyloglucan + H2O rightleftharpoons xyloglucan oligosaccharides. Thus, the two substrates of this enzyme are xyloglucan and H2O, whereas its product is xyloglucan oligosaccharides. This enzyme belongs to the family of hydrolases, specifically those glycosidases that hydrolyse O- and S-glycosyl compounds.