The parliament "is deeply concerned" that Ankara is violating criteria needed to join the European Union "in the light of the backsliding on respect for democracy and rule of law inside Turkey," a resolution approved by MEPs said.
Reviving Turkey's languishing EU membership bid was a key pledge by European leaders in return for Ankara's help in stopping the huge flow of migrants and refugees heading to Europe, mostly from war-torn Syria.
The non-binding resolution passed with 375 votes in favor and 177 votes against, AFP reported.
The EU has faced accusations of selling out its principles by offering to speed up Turkey's EU membership process in exchange for help on the migrant crisis.
But EU officials said they would hold Turkey to EU press freedom and other standards in the accession talks amid increasing worries over President Recep Tayyip Erdogan's tightened grip on power in the country.
"The EU should not be trading away values for an uncertain outcome," said Marietje Schaake, a Dutch MEP from the ALDE liberal group.
"While we must work with Turkey to ensure refugees are properly sheltered, we must do so on its own merits, and not mix it with accession," she said.
The vote comes days after Erdogan lashed out at Europe for giving Turkey "lessons in democracy".