Surname Янссен (Janssen 
, Янссен 
) , across the world, is a widespread family name. The family name Янссен is characteristic of Netherlands, where it is a common surname, Belgium, where it is quite a common surname, and Aruba (explore the name in all countries). Measured by absolute frequency, it is commonest in Netherlands, Germany, and the United States. Very seldom, Янссен is the forename as well as the last name.