The 17-year-old made his first start of the Gunners in their 1-0 Emirates Cup victory over Wolfsburg yesterday.
The young attacking midfielder was impressive and was expected to go out for a spell on loan but Wenger believes he will benefit more from playing in Arsenal's under-21 side.
"He will definitely be here," said Wenger after the match.
"He is 17-years-old and looks very promising, but he needs to work with us now for a year with the first team, to play with the U21s and develop.
"There is a fantastic potential there and he will stay with us."
When asked if Reine-Adelaide could actually break into Wenger's first team, he said: "I don't know.
"Honestly, I don't know. But for me it was a good opportunity to watch him today."
Wenger was delighted with Reine-Adelaide's performance at the Emirates, adding: "In some situations, of course, he has the game of a 17-year-old, but on the other hand he has shown great potential as well.
"He looks very advanced physically and I'm sure that he has learnt a lot from these two days."
