Waldemar Tomaszewski (former spelling Valdemar Tomaševski, born 3 March 1965) is a Polish-Lithuanian politician who is also an activist for the Polish minority in Lithuania and Member of the European Parliament (MEP).

Leader of the Electoral Action of Poles in Lithuania (LLRA), Tomaszewski has been an MEP since 2009.

Finding himself as one of only two LLRA members in the Seimas, during the parliamentary term, he moved between factions, including Homeland Union and Order and Justice.

Receiving 4.7% of the national vote, Tomaszewski finished fourth, with Dalia Grybauskaitė winning comfortably.

Winning 8.4% of the vote, up from 5.7% in 2004, LLRA won its first ever MEP, with Tomaszewski topping the list and being elected.