The Maelbeek (French, pronounced [malbek, -bɛk] ; former Dutch spelling) or Maalbeek (modern Dutch, pronounced [ˈmaːlbeːk]) is a stream that flows through several municipalities in Brussels, Belgium, including Etterbeek, Ixelles, Saint-Josse-ten-Noode, Schaerbeek. It is a tributary of the Senne, which it joins up in Schaerbeek, from its source located to the south near La Cambre Abbey. Maelbeek/Maalbeek metro station is located in the central area of this Maalbeek valley.
The name Maalbeek, meaning "mill brook", comes from the Dutch words beek (meaning "brook") and maal (meaning "to mill"). Molenbeek has a similar derivation. The stream was vaulted in 1872, at which time there were 58 ponds along it. Nowadays, only six are left: the ponds of La Cambre Abbey; of Ixelles (two); of Leopold Park; of Marie-Louise Square; and of Josaphat Park.