Aaltje Noordewier-Reddingius (born Aaltje 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 through the 1930s. She was also a celebrated voice teacher.
From 1886–90, she studied at the Conservatorium van Amsterdam. In 1893, she married painter . She was a mentor to singers such as Aafje Heynis, Erna Spoorenberg and Laurens Bogtman.
Asteroid 677 Aaltje is named in her honour.