The Bayern Munich head coach believes the German goalkeeper would be a great addition to Barca but still thinks Manuel Neuer is the world's best
Earlier in January, Ter Stegen revealed his decision to leave Borussia Monchengladbach after refusing to sign a new deal, which has fuelled speculation that the 21-year-old goalkeeper is to replace outgoing Victor Valdes at Camp Nou.
Barcelona admitted an interest in Ter Stegen in November and Guardiola says that although he is a talented shot-stopper, Neuer is still the very best.
"Ter Stegen is a very good goalkeeper, one of the best in the world," Guardiola told reporters.
"But here at Bayern, we have the best in the world. Manuel Neuer."
Guardiola will be able to see just how good Ter Stegen is when his Bayern side come up against Gladbach in the return of the Bundesliga on Friday.
Ter Stegen has so far been rewarded with three caps for Germany and is a contention for a place at this year's World Cup. However, Neuer remains coach Joachim Low's No.1.