Velsen (Dutch pronunciation: [ˈvɛlzə(n)] ⓘ) is a municipality in the Netherlands, in the province of North Holland.

On the north side of the North Sea Canal there is a major steel plant, Tata Steel IJmuiden, formerly known as Koninklijke Hoogovens (the town of IJmuiden is actually located south of the canal).

The headquarters of the Koninklijke Nederlandse Redding Maatschappij is located in IJmuiden.

The municipality of Velsen consists of the following cities, towns, villages and/or districts: In Velsen, there are the following connections across the North Sea Canal: Also there used to be the Fast Flying Ferry to Amsterdam.

The municipal council of Velsen consists of 33 seats, which are divided now (2022) as follows: The ruins of a Roman naval base at Velsen discovered starting in 1945 are believed to be ancient Flevum,[7][8] which is listed as Phleoum, Romanized to Phleum, in Ptolemy (2.10).