Błaszczyk, Błaszczak, Blaščik, Blaščak, Blashchuk, or Blashchak Blasscyk is a surname.
The surname is derived from Slavic diminutives of the given name Blasius. Błaszczyk and Błaszczak are the standard Polish variants, with Błaszczyk about four times more common. A variant with a Ukrainian/Belarusian ending (-uk) is found at a lower frequency in Poland, mainly in the east.
| Language | Masculine | Feminine |
|---|---|---|
| Blaščik Blaščík Blaščak | Blaščiková Blaščíková Blaščaková | |
| Błaszczyk (pronounced as /pl/) Błaszczak (pronounced as /pl/) | ||
| Ukrainian (Romanization) | Ukrainian: Блащук (Blashchuk, Blaščuk) |