At the 2012 World Championships in Nice, France, Kostner finished third in the short program and first in the free skate with a new personal best score to take the gold. She became Italy's first World champion in ladies' singles and second in any discipline after Fusar-Poli / Margaglio in 2001. Kostner's final event of the season was the 2012 World Team Trophy, where she competed as part of the Italian team. She set a new personal best score in the short program and placed third in the free skate, finishing 2nd overall.