Authentication of Polish diplomas and school certificates,

The education system: if the certificate or diploma is issued by the regional examination body, the authentication is carried out at the Ministry of National Education.

If the certificate or diploma is issued by the school, it is authenticated by the education superintendent.

More information available at https://men.gov.pl/pl/wspolpraca-miedzynarodowa/legalizacja-polskich-swiadectw

In higher education:

Information can be found at

https://nawa.gov.pl/uznawalnosc/uwierzytelnianie-dyplomow and http://www.nauka.gov.pl/en/authentication-legalization-of-polish-diplomas-and-certificates/