Officials at the European Parliament say turnout across all of the bloc’s 28 countries was a 20-year high of 50.5% for Sunday’s vote.
Spokesman Jaume Duch Guillot said the turnout was eight percentage points higher than the last Europe-wide vote for the parliament in 2014.
He said the figures, which include voting from the UK – which aims to leave the bloc, “shows that European citizens realise that the European Union is part of their everyday reality and future”.
With final results still trickling in, it appeared that the parliament’s two long-time centrist political groups saw their support shrink at the expense of the anti-immigration far-right and pro-environment Greens.
That was according to seat projections for the 751-seat parliament that Mr Guillot read aloud from the stage in the parliament building in Brussels.