Norrtälje Municipality (Norrtälje kommun) is a municipality in Stockholm County in east central Sweden. Its seat is located in the city of Norrtälje.

It is the largest and northernmost municipality of Stockholm County and was created in 1971 through the amalgamation of several former municipalities. There are 25 original local government units (as of 1863) combined in the present municipality.

Many of the houses in Norrtälje municipality are summer cottages, only inhabited during summertime. This is due to its geographical location by the Stockholm archipelago, which makes it popular among Stockholmers and tourists.