Carl Johann Wilhelm Neumann (Latvian: Kārlis Johans Vilhelms Neimanis; Russian: Карл Иоганн Вильгельм Нейман; born 5 October 1849 in Grevesmühlen – died 6 March 1919 in Riga) was a Baltic German architect and art historian.

Neumann's family moved to Kreutzburg (then in Russian Empire) during Wilhelm's childhood.

When he was 15 years old, he worked as an apprentice at Paul Max Bertschy's engineering office during the construction of the Riga–Dünaburg Railway.

After this he studied at the Riga Polytechnicum, and beginning 1875 at the Imperial Academy of Arts in Saint Petersburg.

In 1895 he moved to Riga, where numerous prominent buildings in the style of historicism was created, amongst these the Peitav Synagogue.