A doctor is facing up to two years in prison for allegedly insulting President Recep Tayyip Erdogan by sharing pictures of him next to JRR Tolkien's creature on social media.
But Jackson has given a statement to The Wrap website saying that the images used are in fact of Smeagol, the good side of the character.
The director, along with screenwriters Fran Walsh and Philippa Boyens, stated: "If the images below are in fact the ones forming the basis of this Turkish lawsuit, we can state categorically: None of them feature the character known as Gollum.
"All of them are images of the character called Smeagol.”
Lawyer Hicran Danisman told the Associated Press she was forced to argue in court that "Gollum is not a bad character" because she got "nowhere" with a defence case based on freedom of expression.
Ms Danisman said that prompted the judge to rule that a committee, including psychologists and movie experts, should provide an assessment of Gollum's character.
But Jackson said: "Smeagol is a joyful, sweet character. Smeagol does not lie, deceive, or attempt to manipulate others.
"He is not evil, conniving, or malicious — these personality traits belong to Gollum, who should never be confused with Smeagol."
Smeagol/Gollum are played by Andy Serkis in the films but the British actor has not commented on the case.
The trial was adjourned until 23 February.