The Museum aan de Stroom (MAS; Dutch for: Museum on the stream) is a museum located in the Eilandje district of Antwerp, Belgium, opened in May 2011. It is the largest museum in Antwerp.

The 60 metre high MAS, was designed by Neutelings Riedijk Architects. The façade is made of Indian red sandstone and curved glass panel construction. The MAS houses 470,000 objects, most of which are kept in storage. The first visitor's gallery is the "visible store", which contains 180,000 items. The building replaces the Hanzehuis which used to stand on exactly the same spot. International merchants worked and receded at the Hanzehuis. In the nineteenth century a fire destroyed the building.

In 1998 the Antwerp city council decided to build a museum at the Hanzestedenplaats which will be called MAS | Museum aan de Stroom. On September 14 2006 the first brick of the building is laid. In 2010 the museum objects arrive from various other museums like the Etnographic Museum and the Maritime Museum, which both ceased to exist. On May 17 2011 the museum opened for the public.

The central focus of the MAS is Antwerp and its many aspects. The main themes are Metropolis, Power, Life and Death, and Antwerp's long history as a major international port. The museum is committed to informing the public using new media. It has placed QR codes on (groups of) most objects that link to website information in five languages: English, Dutch, French, German and Spanish.

From March to June 2013, an exhibition titled Bonaparte at the Scheldt, was staged at the MAS. The exhibition commemorated Napoleon Bonaparte's involvement with Antwerp from 1803.