The Chelsea striker is currently enjoying a season-long loan spell at Everton, with the Merseyside outfit challenging the likes of Tottenham and Liverpool for a top-four finish.
"I'm turning 21, I've been a professional for five years already. It is time," he told Het Laatste Nieuws. "It is high time that I play in the Champions League. It is the next step I need in my development. Full stop.
"Cristiano Ronaldo and Wayne Rooney were experienced already at that level when they were just 23-24 years old. I want to play Champions League football now. I must now show I'm ready for it.
"I still have two years on my contract and I know Chelsea follow my development. In the end it depends on what the manager thinks about me."
Despite setting his sights on making an impact at Stamford Bridge, Lukaku is still adamant that another loan move after his West Brom success — 17 goals — was key to his development.
He continued: "After the season I had at West Brom, it was important that as a young player I kept developing. That means to play.
"To me there is a difference between playing in 20 or 45 matches a season and scoring 10 or 20 goals. Mourinho eventually understood that. If I can be better than I was last season, what is then holding me back? Then it will be time to play Champions League football, which is what I want to do."