The 22-year-old's tally for the season now stands at 10 in all competitions, and the French coach believes that he has matured both as a player and as a person over the past year.
He also added that the Gunners' days of selling their top players is over.
When asked if he would consider selling Ramsey for £50m, Wenger replied: "No. We don't want to sell anybody, we want to keep the team together.
"I've suffered enough for years for having to sell the players. Now we are in a stronger position financially.
"He keeps surprising me. He has matured as a player and a person as well. We came here in the FA Cup a few years ago and he had a very difficult game. Now he shows how much he has developed as a person."
Ramsey's fine early-season form has played a large part in the North Londoners' rise to the top of the Premier League.