In Italy, wearing red on New Year's Eve is commonly associated with luck, love, and prosperity.
The tradition can involve red underwear, socks, or another item of clothing, with the color treated as a festive charm for the coming year. Customs vary between families and regions, so there is no single required garment or universal rule about how the clothing must be worn.
Red has long carried positive associations in Italian New Year customs, including vitality, passion, and protection from bad fortune. The practice is especially visible in popular fashion and gift traditions around the holiday.
This custom is separate from Italy's food traditions. Lentils are also commonly eaten at New Year's because their round shape resembles coins and therefore suggests financial prosperity. The red-clothing custom is likewise symbolic, not a legal or religious requirement, and many Italians celebrate without following it.