Jean-Claude Juncker has insisted that Turkey must meet all conditions for its citizens to win visa-free travel in Europe, a key plank of the EU-Turkey migrant deal.
The European Commission President said in his address that "visa liberalisation will only happen if all of the necessary conditions are fulfilled by the Turkish side".
But he also called for patience, saying Turkey has tough issues to resolve to meet the conditions - which include redefining what constitutes a terrorist act to ensure that journalists and academics are not targeted.
Turkey has been struck by several suicide bombings and a thwarted military coup in July and President Recep Tayyip Erdogan is refusing to soften his line.
Mr Juncker said he hopes that Ankara will fulfil the visa waiver requirements, but acknowledged it might not happen "necessarily in the set timetable".
The visa waiver was supposed to have been granted in July, but was then delayed until October.
EU and Turkish officials now say they expect it "in coming months".