In Colombia's New Year's Eve tradition, yellow underwear is popularly worn for good luck.
The custom is widely associated with attracting prosperity, happiness, or positive fortune in the coming year. Some people wear the garment inside out before midnight and turn it correctly afterward, while others emphasize wearing new yellow underwear as part of the ritual.
Yellow has strong symbolic associations in many Colombian celebrations, but the underwear tradition is a specifically popular New Year's custom rather than a national legal or religious requirement. Practices vary by family, region, and personal belief.
Colombian New Year's celebrations also include fireworks, family gatherings, special foods, and the construction or burning of Año Viejo figures in some communities. The yellow-underwear custom is therefore one element within a broader set of year-end traditions. It is sometimes confused with red-underwear customs found in parts of Europe and Latin America, where red is linked especially with romance.