Family name Клаассен (Claassen 
, Клаассен 
) , all around the world, is a common last name. The family name Клаассен is habitual in Namibia, where it is quite a common surname, Netherlands, and South Africa. In absolute terms, this name is the most popular in South Africa, Netherlands, and Germany.
| VARIANT | COUNTRY |
|---|---|
| Claassen | Germany, Namibia, South Africa, United States, Netherlands |
| Клаассен | Russia, Ukraine |