Louis II, sometimes called the Younger, was the king of Italy and emperor of the Carolingian Empire from 844, co-ruling with his father Lothair I until 855, after which he ruled alone.

King of Italy was the title given to the ruler of the Kingdom of Italy after the fall of the Western Roman Empire. The first to take the title was Odoacer, a barbarian warlord, in the late 5th century, followed by the Ostrogothic kings up to the mid-6th century. With the Frankish conquest of Italy in the 8th century, the Carolingians assumed the title, which was maintained by subsequent Holy Roman Emperors throughout the Middle Ages. The last Emperor to claim the title was Charles V in the 16th century. During this period, the holders of the title were crowned with the Iron Crown of Lombardy.