Langenthal has a population (as of December 2018) of 15,624.
As of 2010, 19.9% of the population are resident foreign nationals.
Over the last 10 years (2000–2010) the population has changed at a rate of 5.3%.
Migration accounted for 8%, while births and deaths accounted for -0.7%.

Most of the population (as of 2000) speaks German (11,994 or 85.2%) as their first language, Italian is the second most common (484 or 3.4%) and Serbo-Croatian is the third (297 or 2.1%).
There are 108 people who speak French and 5 people who speak Romansh.

As of 2008, the population was 48.6% male and 51.4% female.
The population was made up of 5,672 Swiss men (38.0% of the population) and 1,583 (10.6%) non-Swiss men.
There were 6,299 Swiss women (42.2%) and 1,384 (9.3%) non-Swiss women.
Of the population in the municipality, 4,139 or about 29.4% were born in Langenthal and lived there in 2000.
There were 4,236 or 30.1% who were born in the same canton, while 2,618 or 18.6% were born somewhere else in Switzerland, and 2,674 or 19.0% were born outside of Switzerland.

As of 2010, children and teenagers (0–19 years old) make up 19.7% of the population, while adults (20–64 years old) make up 61.6% and seniors (over 64 years old) make up 18.7%.

As of 2000, there were 5,805 people who were single and never married in the municipality.
There were 6,633 married individuals, 941 widows or widowers and 699 individuals who are divorced.

As of 2000, there were 2,277 households that consist of only one person and 365 households with five or more people.
In 2000, a total of 6,080 apartments (91.2% of the total) were permanently occupied, while 327 apartments (4.9%) were seasonally occupied and 261 apartments (3.9%) were empty.
As of 2010, the construction rate of new housing units was 6.2 new units per 1000 residents.
The vacancy rate for the municipality, in 2011, was 1.2%.

The historical population is given in the following chart:
Langenthal has a population (as of December 2018) of 15,624. As of 2010, 19.9% of the population are resident foreign nationals. Over the last 10 years (2000–2010) the population has changed at a rate of 5.3%. Migration accounted for 8%, while births and deaths accounted for -0.7%.
Most of the population (as of 2000) speaks German (11,994 or 85.2%) as their first language, Italian is the second most common (484 or 3.4%) and Serbo-Croatian is the third (297 or 2.1%). There are 108 people who speak French and 5 people who speak Romansh.
As of 2008, the population was 48.6% male and 51.4% female. The population was made up of 5,672 Swiss men (38.0% of the population) and 1,583 (10.6%) non-Swiss men. There were 6,299 Swiss women (42.2%) and 1,384 (9.3%) non-Swiss women. Of the population in the municipality, 4,139 or about 29.4% were born in Langenthal and lived there in 2000. There were 4,236 or 30.1% who were born in the same canton, while 2,618 or 18.6% were born somewhere else in Switzerland, and 2,674 or 19.0% were born outside of Switzerland.
As of 2010, children and teenagers (0–19 years old) make up 19.7% of the population, while adults (20–64 years old) make up 61.6% and seniors (over 64 years old) make up 18.7%.
As of 2000, there were 5,805 people who were single and never married in the municipality. There were 6,633 married individuals, 941 widows or widowers and 699 individuals who are divorced.
As of 2000, there were 2,277 households that consist of only one person and 365 households with five or more people. In 2000, a total of 6,080 apartments (91.2% of the total) were permanently occupied, while 327 apartments (4.9%) were seasonally occupied and 261 apartments (3.9%) were empty. As of 2010, the construction rate of new housing units was 6.2 new units per 1000 residents. The vacancy rate for the municipality, in 2011, was 1.2%.
The historical population is given in the following chart:
Langenthal