Aaltje Noordewier-Reddingius (1 September 1868, Deurne – 6 April 1949, Hilversum) was a noted Dutch classical soprano who had an active performance career in the concert repertoire from 1888 up into the 1930s. She was also a celebrated voice teacher. From 1886–1890 she studied at the Conservatorium van Amsterdam. In 1893 she married painter Michiel Noordewier.
She was a mentor to singers such as Aafje Heynis and Laurens Bogtman.
Asteroid 677 Aaltje is named in her honour.