Ziyech has been feuding with Morocco national team coach Vahid Halihodzic since June last year and was overlooked for the recent Africa Cup of Nations in Cameroon, where the Atlas Lions were eliminated by Egypt in the quarterfinal stage.
Ziyech was born in the Netherlands to Moroccan parents and played for the youth teams of his country of birth before switching to the African side.
The 28-year-old won 40 caps for Morocco, scoring 17 goals and represented them at the 2018 FIFA World Cup and 2019 Africa Cup of Nations.
He has now decided to focus on his club career amid a war of words with Halihodzic.
"I understand them, but I will not return to the Moroccan national team and this is my final decision," Ziyech told ADSportsTV.
"It's all clear for me how things are going over there and I am focusing on what I am doing and, right now, that is my club.
"At the end of the day, it's a decision he makes and you have to respect it. All the lying that comes with it, it's, for me, clear and I will not return to the national team.
"I understand and feel sorry for [the fans], but that's the situation we're in."
Ziyech has played 25 times in all competitions for Chelsea this season, scoring six goals.
