Marek Siwiec
 Marek Maciej Siwiec (born on 13 March 1955 in Piekary Slaskie) is a Polish politician and since 2004 Member of the European Parliament for the Greater Poland Voivodship with the Democratic Left Alliance-Labor Union part of the Socialist Group and sits on the European Parliament's Committee on Foreign Affairs. In the European elections of 2004 he obtained 36 985 votes.