Sudipen (Southern Ilocano pronunciation: [su'dipɯn]), officially the Municipality of Sudipen (Ilocano: Ili ti Sudipen; Filipino: Bayan ng Sudipen), is a municipality in the province of La Union, Philippines. According to the 2020 census, it has a population of 17,187 people.

By virtue of Executive Order No. 72 signed by President Manuel Roxas on July 30, 1947, the municipal district of Sudipen, along with San Gabriel and Pugo, was organized into a regular municipality. As a result, the fourteen municipalities of La Union, all established under the Revised Administrative Code, were increased to seventeen.

Sudipen is located 312 kilometres (194 mi) north-north-west of the Philippine capital, Manila, and 43 kilometres (27 mi) away from the provincial capital of San Fernando, La Union. It is bounded on the west by the municipalities of Bangar and Balaoan; on the east and north by the Amburayan River and the province of Ilocos Sur; and in the south by Santol.

Sudipen has a total land area of 97 square kilometers, making it the fifth largest municipality by land area in the province.  Barangay Bulalaan is the largest barangay with a land area of 8,988 hectares (22,210 acres), while Barangay Poblacion is the smallest with only 82 hectares (200 acres).

Sudipen is politically subdivided into 17 barangays.  Each barangay consists of puroks and some have sitios.

Population census of Sudipen

Year	Pop.	±% p.a.
1918	3,569	—
1939	6,039	+2.54%
1948	6,922	+1.53%
1960	7,926	+1.13%
1970	9,785	+2.13%
1975	10,430	+1.29%
1980	10,796	+0.69%
1990	13,043	+1.91%
1995	14,075	+1.44%
2000	15,099	+1.52%
2007	15,949	+0.76%
2010	16,531	+1.31%
2015	17,056	+0.60%
2020	17,187	+0.15%
Source: Philippine Statistics Authority

In the 2020 census, the population of Sudipen was 17,187 people, with a density of 180 inhabitants per square kilometre or 470 inhabitants per square mile.

Poverty incidence of Sudipen

10 20 30 40 2006 33.10 2009 25.82 2012 14.73 2015 9.66 2018 3.95 2021 11.29 Source: Philippine Statistics Authority

Sudipen, belonging to the first congressional district of the province of La Union, is governed by a mayor designated as its local chief executive and by a municipal council as its legislative body in accordance with the Local Government Code. The mayor, vice mayor, and the councilors are elected directly by the people through an election which is being held every three years.

Members of the Municipal Council
(2019–2022)

Position	Name
Congressman	Pablo C. Ortega
Mayor	Wendy Joy D. Buquing
Vice-Mayor	Melvin G. Macusi
Councilors	Tita D. Mostoles
	Edwin M. Belisoa Jr.
	Joebet L. Dee
	Demy L. Danguecan
	Thelma R. Peña
	Bery A. Yadao
	Marcelina P. Leonen
	Yna P. Castro

• 
  Municipal hall
• 
  Town center
• 
  Sudipen Farmers Public Market
• 
  Sudipen Central School
• 
  Sudipen terminal

• Philippine Standard Geographic Code
• Philippine Census Information
• Local Governance Performance Management System