Niels Arp-Nielsen (28 May 1887 – 23 May 1970) was a Danish architect.
Niels Peter Edvard Arp-Nielsen was born at Frederiksberg, Denmark.
From 1903-1906, he attended Technical University of Denmark in Copenhagen and was trained at the Royal Danish Academy of Fine Arts from 1906-1915.
Arp-Nielsen had an independent firm from 1915.
He exhibited at Charlottenborg Spring Exhibition 1920-1922.
Building designs include the Nordisk Film Company's office and factory in Copenhagen Freeport (1915) and the Trade and Agriculture Bank in Slagelse (1922).