Most of the 18 students and a faculty member from the Middle East Technical University (METU) were charged with "refusing to disperse" after being arrested at a May 10 Pride march by police using pepper spray, plastic bullets and tear gas.
The trial highlights ongoing limits on LGBT+ events in Turkey. After a 2016 coup attempt, local governments were given the power to ban public gatherings, which authorities across the country have used to outlaw Pride marches.
Defence lawyer Oyku Didem Aydin demanded the immediate acquittal of the defendants while standing before coloured case files arranged to create a large rainbow on her desk.
"The images in the indictment only show students using their basic rights and freedoms," Aydin told the court. "There's no resistance to police.
"The defendants are on trial for freedom of expression, for their freedom of assembly. No one should face such a thing."
The judge refused and adjourned the case until March 12 2020.
Homosexuality is legal in Turkey, home to a diverse LGBT+ community that includes refugees who fled neighbouring countries including Iran, where they can be sentenced to death.