Nittedal is a municipality in Akershus county, Norway. It is part of the traditional region of Romerike. The administrative centre of the municipality is the village of Rotnes. The parish of Nitedal was established as a municipality on 1 January 1838 (see formannskapsdistrikt).
The name (Old Norse: Nitjudalr) is an old district name. The first element is the genitive case of the river name Nitja (now Nitelva) and the last element is dalr which means "valley" or "dale". The meaning of the river name is unknown. Prior to 1918, the name was written "Nittedalen". The coat-of-arms is from modern times. They were granted on 23 January 1987. The arms show the two silver lines running in a bend sinister direction on a green background.