"After consultations, the High Negotiations Committee agreed to go to Geneva. The delegation is expected to arrive on Friday," said Riad Naasan Agha, a spokesman for the main opposition body.
The opposition had been reluctant to attend the indirect peace negotiations, citing violations by government forces of a ceasefire in place since February 27.
"We have noticed a sharp decline in ceasefire violations in recent days and progress in the humanitarian file," particularly with regards to aid deliveries to besieged towns, Agha said.
"We find that the international community is insisting that all the sides, especially Russia and the regime, must respect the truce," he added.
The announcement comes a day after regions of Syria covered by the ceasefire enjoyed the "calmest day" since the truce started, according to the Syrian Observatory for Human Rights.
