Cognomen Siefker (Siefker 
) , in all the world, is quite a rare surname. The last name Siefker is characteristic of the United States, where it is a rare surname, Germany, and Canada, where it is a very rare surname.
| VARIANT | COUNTRY |
|---|---|
| Siefker | New Zealand, Germany, United States, Canada |
| phyllis k. siefker (b. 1941) |
|
|
| birgitta maria siefker-eberle German diplomat, DE (b. 1954) |
|
|
| andrew joseph siefker Ph.D. Arizona State University 1997 |
|