Terry is facing an FA independent regulatory hearing into a charge that he used racist language towards QPR's Anton Ferdinand in October last year.
The 31-year-old was accompanied by Chelsea chairman Bruce Buck at the hearing at Wembley Stadium this morning, and the defender departed shortly after 1pm.
He is expected to return on Wednesday to hear evidence in his favour - with team-mate Ashley Cole likely to be called upon again to testify.
Cole gave evidence that helped exonerate Terry in his Westminster Magistrates' Court case in July related to the same incident, telling the court: "We shouldn't be sitting here."
Meanwhile, former Chelsea coach Ray Wilkins, who also testified on the defender's behalf in court, has said he is prepared to go to the FA hearing to support the player, who announced his international retirement on Sunday.
Wilkins told ESPN: "I called John immediately after his decision to resign from the England team to see how he is. We didn't talk about my attendance at the FA hearing, but I am there for him if he needs me.
"I gave evidence on his behalf at the magistrates' court and I would do so again at the FA hearing, if they wish me to."
Watch: Terry's hearing will go third day... More Videos
The case centres around an incident during Chelsea's Barclays Premier League defeat at QPR on October 23 last year when Terry and Ferdinand clashed verbally on a number of occasions.
It set in motion a train of events that saw:
:: Terry charged with an offence by the Crown Prosecution Service :: stripped of the England captaincy :: the subsequent resignation of Fabio Capello as England manager in protest :: questions surrounding Terry's inclusion in the Euro 2012 squad and Rio Ferdinand's omission.
Terry was found not guilty in July of a racially-motivated public order offence with the prosecution unable to prove he had called Ferdinand a "f****** black c***" as an insult.
Terry admitted using the words, but insisted he had only been repeating words he thought Ferdinand had accused him of saying.
The FA's decision to press ahead with their own charges infuriated Terry to the extent that on the eve of the disciplinary hearing he announced he was quitting international football with immediate effect, saying his position was "untenable".
Terry's legal team had argued the governing body's own rules dictated his acquittal in court means the case cannot proceed but the FA believed their charge was distinct from the court charge.
The panel who handed Liverpool striker Luis Suarez an eight-match ban when they found him guilty of racially abusing Manchester United defender Patrice Evra last season declared at that time that simply using racist language was enough to constitute a breach of FA rules.