Retweeting an insulting tweet on the social networking site also constitutes an offence of defamation. Because elements of the crime of defamation were formed in a chained way. You can look at the example Supreme Court decision.

18. Criminal Department

Basis Number : 2015/10377

Decision Number: 2015/12777

“text of jurisprudence”

Court :Magistrate’s Court
Offense: insult
Provisions: acquittal, conviction

The provisions given by the Local Court were appealed, the duration of the applications and the nature of the decision and the date of the crime were discussed:
The appeal was overturned because there were no grounds for refusal.
In the examination according to the minutes, documents and content of the justification reflecting the hearing process in which conscientious blood is formed,
In the face of the defendant’s defense, which does not correspond to the usual flow of life, the insulting words about the participants were thrown out of the defendant’s own twitter account and did not participate in the thinking in the communique.
1 – Defendant… the action of the insult obligations of the mandatory elements of a solution that is reached through the right sword and this action was committed by the defendant conducted in accordance with the law, with all the evidence that showed the results of the trial in stages to provide complete control and forth in the claims and defenses of the appeal of exhibited and discussed without changing the essence, blood, conscientious, precise, consistent and do not conflict where the data on which it is based,
That the act qualifies as correct and complies with the type of crime prescribed by law,
Although it is understood that the act of defamation was carried out because of the duty of the participant, who was the governor of Adana at the time, it was not thought that the application should be made according to Article 125/3-a of the TCK, but the violation cannot be made because there is no counter-appeal,
As it is understood, the defendant … is not seen in the place of thought in the communique with the reasons put forward by his defense, and the conviction is upheld by the fundamental rejection of the appeal case,
2-as for the appeal of the sentence established against the defendant … ;
Other reasons have not been seen in place.

But;
The defendant, on the social networking site called twitter tweet shared by retweeted of the other defendants, to be fixed by your own admission, in the face of a public officer for assignment to any of the elements of the crime of insult in a manner to occur without chaining, instead of granting the defendant’s conviction acquittal,
It was unanimously decided on 07/12/2015 that the sentence should be broken, that the trial should be continued starting from the pre-trial stage and that the file should be sent to the main/sentencing court to be concluded.