The Bethaniënklooster is a former 15th-century monastery in the Wallen red-light district in Amsterdam. It is one of the few remains of the once-expansive area of monasteries that dominated the oudezijde ("old side") of town in the Middle Ages. The monastery was devoted to Mary of Bethany (Mary Magdalene) and, at its largest extent, encompassed the entire area between Bloedstraat and Oude Hoogstraat streets to the north and south and Oudezijds Achterburgwal and Kloveniersburgwal canals to the west and east.
The only surviving remains of the monastery are the northern wing in Barndesteeg alley and some wall fragments in Gedempte Huidenvetterssloot alley. The building in the Barndesteeg is now in use as a concert hall. Some 120 concerts are held there yearly, attracting 5,000 to 10,000 visitors. In addition to concerts, lectures, weddings and other gatherings are also held there. The building has two storeys which have been largely joined into a single hall. It also has a vaulted crypt which still largely dates to around 1450, when the monastery was founded. The attic is now used as student accommodation. The building has held rijksmonument status since 1970.
The street names Bethaniënstraat, Bethaniëndwarsstraat, and Koestraat are reminders of the monastery. The name "Koestraat" ("Cow Street") is a reminder of the cattle that was raised by the nuns as livestock for the meat served at banquets of the schutterijen (citizen militia companies).