Marc Sleen Museum, Comics museum in Zandstraat, Brussels, Belgium.

The Marc Sleen Museum displays over 15,000 original drawings and artworks created by Belgian comic artist Marc Sleen and his famous character Nero. The collection includes sketches, manuscripts, and published works that document different phases of his artistic career.

The museum opened on 19 June 2009 in the former offices of the newspaper Le Peuple at 33–35 rue des Sables/Zandstraat, a building rebuilt in 1931 by Fernand and Maxime Brunfaut. Marc Sleen had begun drawing there in 1947 for De Nieuwe Gids. King Albert II attended the opening. After low visitor numbers, it closed permanently in 2024, its collection passing to the Belgian Comic Strip Center.

The museum's name and its Nero walking route, run since 2011, follow locations from the albums, including the Black Tower, the Palace of Justice, the Chapel Church, the Sablon, the Central Station, the Grand-Place and Manneken Pis. The album Het Spook uit de Zandstraat, set in the museum building, was reissued in 2009 with a new cover by Dirk Stallaert showing the museum.

The museum occupied the former offices of the newspaper Le Peuple at 33–35, rue des Sables/Zandstraat, directly across from the Belgian Comic Strip Center. The building was designed in 1905 by Richard Pringiers and rebuilt in 1931 by Fernand and Maxime Brunfaut. It closed permanently in 2024, so the site is no longer open to visitors.

The building at 33–35 rue des Sables/Zandstraat was designed in 1905 by architect Richard Pringiers for the newspaper Le Peuple, then rebuilt in 1931 by Fernand and Maxime Brunfaut. Sleen's 1996 album Het Spook uit de Zandstraat is set in this very building; the museum reissued it in 2009 with a new cover by Dirk Stallaert showing the museum in the background.