Belgium's appeal court on Thursday rejected a legal objection to an earlier ruling which said activities by the PKK in Europe could not be classed as terrorism.
The Belgian Federal Prosecutor's office in 2016 appealed a Brussels court ruling that PKK activities could not be classed as terrorism but as an "armed campaign".
The court in November had refused the prosecutor's request to send 36 alleged PKK members to a higher criminal court, saying an "armed campaign cannot be considered as terrorist acts".
The decision was made despite the group being listed as a terrorist organization by the EU, the U.S. and Turkey.
The suspects are accused of kidnapping children from their families in Belgium and European countries, and sending them to Greece and Iraq for training.
They are also accused of forging documents and extorting businessmen.
Among those standing trial are Remzi Kartal and Zubeyir Aydar, accused of being senior members of the PKK's European arm. They were among PKK suspects arrested in March 2010 in raids on 18 addresses across Belgium.
The court case began in October 2015 following an investigation that began in 2006.
Belgium has been criticized in the past for failing to act against the PKK.
In August last year, the movement's supporters in Brussels were allowed to celebrate the anniversary of the terror group's first attack in 1984.
Five months earlier PKK sympathizers had been allowed to set up tents outside EU buildings ahead of a Turkey-EU summit.
