Moyes hails Belgian playmaker's performance so far this season.
"Marouane is probably the best midfielder in the country at the moment," Moyes said to the Daily Express. "He is playing as well as anyone.
"His performances of late have been excellent," the Scotsman added. "His experience of the Premier League is improving and he is doing really well."
Fellaini was signed from Standard Liege in 2008.
"I thought the first half of the season would be the worst for him," Moyes added.
"He had such a good first season and scored a lot of goals but I can see signs now that he is beginning to get to top form and be good for the team."
Moyes has supplemented his Toffees ranks with the temporary purchase of American forward Landon Donovan.
Alan Dawson, Goal.com