Family name Joncker (Younker 
, Joncker 
) , globally, is quite a rare cognomen. The surname Joncker is habitual in Canada, where it is a rare surname, the United States, and Belgium.
| VARIANT | COUNTRY |
|---|---|
| Younker | New Zealand, United States, Romania, Israel, Canada |
| Joncker | United States, France, Belgium, Germany, Canada |
| ulrich joseph joncker BE (b. 1879) |
|
|
| théo de joncker Belgian conductor (1894-1964), BE (b. 1894) |
|