Although the resolution repeated language previously adopted by the parliament in 1987, it could raise tensions with Turkey, whose President Tayyip Erdogan said even before the vote took place that he would ignore the result.
After the vote, the Turkish Foreign Ministry accused the parliament of attempting to rewrite history.
Muslim Turkey agrees Christian Armenians were killed in clashes with Ottoman soldiers that began on April 15, 1915, when Armenians lived in the empire ruled by Istanbul, but denies that this amounted to genocide.
Armenia, some Western historians and foreign parliaments refer to the mass killings as genocide.
Voting by show of hands, European lawmakers overwhelmingly backed the motion stating that the "tragic events that took place in 1915-1917 against the Armenians in the territory of the Ottoman Empire represent a genocide".
Pope Francis sparked a diplomatic row last Sunday by calling the killings "the first genocide of the 20th century." His remarks prompted Turkey to summon the Vatican's ambassador to the Holy See and to recall its own.
The European Parliament sprang to the Pope's defense, commending the message the pontiff delivered at the weekend.
Turkey is a candidate country to join the 28-nation EU but accession talks have dragged on for years with little progress.
Earlier, Erdogan told a news conference that "whatever decision the European Parliament takes on Armenian genocide claims, it would go in one ear and out the other".
"It is out of the question for there to a stain, a shadow called 'genocide' on Turkey," he said at Ankara airport before departing on a visit to Kazakhstan.
Then prime minister Erdogan last year offered what his government said were unprecedented condolences to the grandchildren of Armenians killed in World War One.
The parliament's resolution said such statements were a step in the right direction, but legislators urged Turkey to go further and to recognize the events as genocide.
"We shouldn't forget that people were murdered and that these particular events are rightly described as a genocide … I believe this should lead to a further recognition by Turkey that there was a genocide under the Ottoman empire," German Christian Democrat Elmar Brok said.
In a statement after the vote, Turkey's foreign ministry said lawmakers who backed the resolution were in partnership with "those who have nothing to do with European values and feeding on hatred, revenge and the culture of conflict".
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By Adrian Croft and Ayla Jean Yackley. Additional reporting by Humeyra Pamuk and Ece Toksabay in Ankara, Francesco Guarascio in Brussels; Editing by Catherine Evans. http://news.yahoo.com/turkeys-erdogan-says-disregard-european-view-armenian-killings-083736104.html