Demel believes the time is right to quit international football so that he can give his all to Sam Allardyce's side.
"I have decided to quit international football and it was not an easy decision for me," Demel told Sky Sports. "I have enjoyed playing for my country and going to the 2006 and 2010 World Cup and my country means a great deal to me.
"I wish Ivory Coast success in the future and I hope they do well at the Africa Cup of Nations.
"However, I am now 31 and it feel it is the right to quit so that I can concentrate on West Ham.
"Last season I was injured a lot and I want to prepare and make sure I perform for West Ham in the Premier League."