The City number two goalkeeper started in the FA Cup final loss to Chelsea.
But Guardiola has no plans to drop Steffen for the clash with Spurs.
Guardiola told reporters: "He's going to play in the League Cup final for sure.
"He made a good save, brilliant with his feet. The goal, one save, and that's all.
"We had more time but unfortunately we could not be more clear in the final third with the final pass.
"We were there until the end. They made good counterattacks. They controlled at the start of the second half but no more than that."