Turkey's president says all suspected coup plotters and "terrorists" will have to wear an almond-brown uniform when they appear in court.
Recep Tayyip Erdogan said jumpsuits would be worn by those accused of involvement in the July 2016 coup plot.
Other "terrorists" would wear jackets and trousers. That term is used for followers of US-based Islamic cleric Fethullah Gulen and for Kurdish rebels.
Last month a defendant wearing a "Hero" T-shirt appeared before a judge.
Police later detained nearly 30 people for wearing T-shirts with the word "hero" on them, the CNNTurk news channel reported.
"There will be no more coming into court wearing whatever they want," Mr Erdogan said in a speech in the eastern town of Malatya.
On the 15 July anniversary of the coup attempt, he demanded a prisoner uniform "like in Guantanamo". The US prison for alleged jihadists makes inmates wear bright orange jumpsuits.
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Mr Erdogan says Turkey must root out all the "Gulenists" blamed for the coup plot in which at least 260 people died. Rogue officers tried to topple him and bombed parliament in a night of bloodshed.
He said defendants were "lying all the time" in court.
More than 50,000 people have been detained and 150,000 public servants suspended from work in a post-coup purge.
There has been strong international criticism of the sweeping crackdown, enacted under a state of emergency.