Family name לאסן (Lacen 
, Lassen 
, Lasn 
) , worldwide, is a common cognomen. The cognomen לאסן is characteristic of Northern Europe, particularly Denmark, where it is quite a common surname, Estonia, and Norway, where it is quite a rare surname. Not in comparison with a country's population, this name is the most popular in Denmark, the United States, and Germany. Much less frequently, לאסן is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Lacen | Germany, Morocco, Brazil, United States, Algeria |
| Lassen | Denmark, Germany, Norway, Brazil, United States |
| Lasn | Canada, United States, Estonia |
| לאסן | Israel |