Walcott is refusing to sign a new contract with his existing deal set to expire next summer and has been linked with a transfer to Liverpool and Manchester City. But Wenger insisted the 23-year-old England winger will stay at Emirates Stadium and is confident he will sign a new contract.
"The situation is simple, Theo will stay with us and play with us," he said.
Wenger was evasive on the subject of whether he planned to make any new signings before the conclusion of deadline day on Friday.
"We are active, but we don't want to just bring average players in. If we find someone special we will sign him," he said.
"Of course we have enough players, but you always want to improve your squad. If you find a top, top player you do it.
"We have the resources to do it, but we are happy with the quality of the squad if we don't buy anyone.
"It's important to believe in our players and to get our long-term injuries back."
Defender Laurent Koscielny returns to the squad after recovering from a calf injury but goalkeeper Wojciech Szczesny faces a fitness test on his rib problem.