MEPs say the EU is committed to the 2015 Paris agreement on climate change.
They voted for a resolution in favour of sticking to the accord after US president Donald Trump said he would pull out of the deal.
Governments from nearly two hundred countries agreed to cut greenhouse emissions.
“The EU will not renegotiate the Paris agreement, the 29 articles of the agreement must be implemented and not renegotiated. Climate action doesn’t need more distractions,” said European Commission president Jean-Claude Juncker.
The deal aims to keep an increase in global warming “well below” 2.0C, compared to pre-industrial levels.
Without the US onside, questions remain how that can be done.
The Paris deal says wealthy countries should help poor nations financially to cope with climate change.