Selahattin Demirtas of the Peoples' Democratic Party (HDP) went on trial in Ankara on charges of links to outlawed Kurdish rebels, claims his party says are politically motivated.
But Demirtas was not present as trial got under way at the Sincan prison complex in Ankara province, in what his party said was a delibate bid to silence the charismatic politician.
The judge said he refused to appear via video link. The court ruled he had to stay in jail and set the date for the next hearing as February 14.
Before his arrest Demirtas was considered one of President Recep Tayyip Erdogan's major rivals, a silky orator who has succeeded in bringing his party from the fringe into the political mainstream.
Demirtas, 44, is charged with "managing a terror organisation", "making propaganda for a terror group" and "inciting criminal acts" among other accusations.
He faces up to 142 years in prison if convicted.