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 Michiel Noordewier.
She was a mentor to singers such as Aafje Heynis, Erna Spoorenberg and Laurens Bogtman.