The Belgium coach believes the pair have improved since moving to the Premier League, and has underlined the importance of playing in front of packed stadiums weekly
Fellaini, who is in the midst of his fifth season with the Toffees, was joined by his compatriot on Merseyside over the summer.
And, having named both players in his most recent squad, Wilmots has hailed the pair's development in the Premier League.
He told Everton's official website: "Every big championship with its packed stadiums is good for the development of our players. Whether it is England, Germany, Italy... it helps the players [to be at the] top level and they bring this experience to the national team.
"When I heard Kevin [Mirallas] would be moving to Everton I thought it was a good transfer and I think he is enjoying himself because there is also Marouane [Fellaini] there as his fellow countryman.
"He [Mirallas] was also good at Olympiakos where he was top goalscorer and he is very young and keeps on growing and improving. The Premier League level is very interesting to him.
"He is fast, he can dribble, he can score and he lets other players score too. He can play different styles and formations and it doesn't affect his level. He will keep improving."