The funds were promised to the eastern nation because of its bid to become an EU member, but could now be withdrawn as that possibility appears more remote.
Turkey was meant to receive €217 million for reforms, infrastructure and agriculture in 2018, but the funds could be slashed over its human rights record.
The European Parliament voted to cut €50 million at first before cutting the extra €30 million if human rights in Turkey do not improve.
National leaders are expected to sign off on the cuts after agreeing to reduce aid to EU candidate countries at last week’s Brussels summit.
Centre-right European Parliament member Siegfried Muresan led the discussions on financial aid to Turkey.
He said: “Turkey is not respecting freedom of speech, freedom of expression, human rights and is drifting further away from European democratic standards. We cannot pretend we don’t see that.”
German Chancellor Angela Merkel said the rule of law in Turkey was “moving in the wrong direction” and its human rights record was “unacceptable” at the recent Brussels summit.
The decision to reduce funding to Turkey was made on the same day that Turkey tried 11 human rights activists in Istanbul amid a large-scale purge following the military coup attempt against President Erdogan in 2016.
The funding reduction comes days after regional European leaders gathered in Finland to bemoan the huge reductions to the EU budget to come after Britain stops paying in.
Regional leaders met in Helsinki for the Conference of Peripheral Maritime Regions (CPRM), where they questioned the impact of Brexit on the EU budget.
Come March 2019, when Brexit is finalised, the EU’s €1trillion budget will be severely depleted, which could be bad news for for some of the smaller regions of the member countries.
The 160 regional presidents gathered in Finland have expressed concerns about what the budget reduction could mean for them.
Enrico Rossi, the President of Tuscany, warned the CPRM that they could see funding collapse in the wake of Britain’s exit from the EU.
But he said: “Regions can not pay the price for emergencies linked to challenges such as immigration, security and defence, renouncing cohesion policies and European solidarity.”
He asked other leaders to come up with new sources for EU funds to fill the hole left by Britain’s departure, saying: “Personally, I think a tax on financial transactions should be seriously considered.”
The CPRM will meet with EU Commission boss Jean-Claude Juncker to remind him of the regions’ needs in the coming months as they worry what Brexit will mean for their bank balance.