Mariagerfjord Municipality (Danish: Mariagerfjord Kommune) is a municipality (Danish, kommune) in North Jutland Region in Denmark.

On 1 January 2007 Mariagerfjord municipality was created as the result of Kommunalreformen ("The Municipal Reform" of 2007), consisting of the former municipalities of Arden, Hadsund and Hobro, and the major part of Mariager, and a very small part of Aalestrup and a very small part of Nørager municipality.

The municipality consists of the land around Mariager Fjord, its namesake.

Mariagerfjord's municipal council consists of 29 members, elected every four years.

This article about a location in the North Jutland Region (Denmark) is a stub.