Holbæk Municipality (Danish: Holbæk Kommune) is a kommune in northwestern Region Sjælland on the island of Zealand in Denmark. The municipality includes the island of Orø, and covers an area of 583 km², and has a total population of 74,129 (2024). Its mayor is Christina Krzyrosiak Hansen, a member of the Social Democrats and the youngest mayor ever in Denmark. The main town and the site of its municipal council is the city of Holbæk. On 1 January 2007 Holbæk municipality was, as the result of Kommunalreformen ("The Municipal Reform" of 2007), merged with existing Jernløse, Svinninge, Tornved, and Tølløse municipalities to form a new Holbæk municipality.

Holbæk's municipal council consists of 31 members, elected every four years. The municipal council has seven political committees.

Below are the municipal councils elected since the Municipal Reform of 2007.

Election	Party									Total seats	Turnout	Elected mayor
	A	B	C	F	I	L	O	V	Ø
2005	9	5	1	2			2	12		31	69.2%	Jørn Sørensen (B)
2009	11	1	2	4			3	10			66.7%	Søren Kjærsgård (V)
2013	10	2	1				4	12	2		71.4%
2017	9	3	1	1	2	3	4	6	2		73.7%	Christina K. Hansen (A)
Data from Kmdvalg.dk 2005, 2009, 2013 and 2017

The ten largest urban areas in the municipality are:

#	Locality	Population
1	Holbæk	27,055
2	Jyderup	3,937
3	Tølløse	3,797
4	Svinninge	2,741
5	Vipperød	2,252
6	Regstrup	2.052
7	Mørkøv	1,806
8	Gislinge	1,442
9	Store Merløse	1,197
10	Undløse	1,149

The number of inhabitants on 1 January:

• 1980 - 29,578
• 1985 - 30,154
• 1990 - 31,151
• 1995 - 32,485
• 1999 - 33,555
• 2000 - 33,864
• 2003 - 34,500

• 
  Holbæk from the air
• 
  Brorfelde
• 
  Eriksholm Castle
• 
  Knabstrup Manor

• Official website (in Danish)
• Municipal statistics: NetBorger Kommunefakta, delivered from KMD aka Kommunedata (Municipal Data)
• Municipal mergers and neighbors: Eniro new municipalities map