Family name Sierak (Sierak 
) , worldwide, is a rare cognomen. The surname Sierak is habitual in Poland, where it is a rare surname, Australia, and Argentina, where it is a very rare surname. Measured by absolute frequency, the name is most common in Poland, the United States, and Australia. Also, Sierak is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Sierak | Poland, France, Australia, United States, Argentina |
| jerzy sierak PL (b. 1955) |
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| krzysztof sierak PL (b. 1966) |
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| lexy sierak researcher (library collections & access) |
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