Vlaar was one of Holland's star performers in Brazil as they finished in third place after losing on penalties in the semi-finals against Argentina.
The defender's performances for Holland have seen him linked with a move away from Villa Park this summer with Vlaar entering the final of his contract.
Okore was not surprised by Vlaar's showings in Brazil and he is hoping Vlaar will stay at Villa and help them next season.
"I was not surprised he played that good," said Okore.
"But I am really glad for him. I hope he can bring us some of that back to us and help us perform like he did throughout the summer.
"I know he will come back with plenty of confidence and belief. I know he can carry it on.
"I think that will rub off on the whole squad. He was superb.
"Ron really showed his true potential at the World Cup.
"But this past season he played really well for us at Villa and it continued into the World Cup."