Mourinho has become embroiled in a dispute with Fifa in recent weeks over claims that the award for Coach of the Year was flawed, with winner Vicente del Bosque branding the Portuguese's suggestions as "childish".
Terim will face off with Mourinho in the Champions League quarter-finals next week, and the 59-year-old has defended his counterpart ahead of the clash.
“He has a different type of personality from most people and that means that sometimes, people don’t understand him,” Terim told Galatasaray TV.
“He is a great coach and he succeeds everywhere he goes. My friendship with him is important to me.”
The former Turkey boss added that his side must brave against the nine-time European champions if they are to get anything out of the game.
“You have got to out to Spain thinking of a good result in hand," he said. "We are a brave team and we are not afraid of any opponent. We must defend and attack [very well] if we are to have a chance against Madrid.”