EU/EEA students do not need Polish visa to study in Poland, however they should apply for a temporary residence permit if they wish to stay in Poland longer then 90 days.
If you are a citizen of one of the following countries you also do not need to have a Polish visa (due to the international agreements):
Andorra,Antigua and Barbuda, Argentina, Australia,
The Bahamas, Barbados, Brazil, Brunei Darussalam,British Nationals (Overseas).
Canada, Chile, Costa Rica, Croatia, Special Administrative Region of the People's Republic of China: Hong Kong SAR, Macao SAR,
Malaysia, Mauritius, Mexico, Monaco,
Nicaragua, New Zealand,
Salvador, San Marino, Saint Kitts and Nevis, Seychelles, Singapore, South Korea