Blackening is a traditional wedding custom practiced in the days or weeks before marriages in rural areas of Scotland and Northern Ireland.

The bride and/or groom are "captured" by friends and family, covered in food or other sticky substances, and then shown publicly so the community can see them. Often, the couple is driven in the back of an open truck, while the people who "capture" them make loud noises by clanging pots and pans. There are no strict rules for the blackening itself, but the couple must be made messy and uncomfortable, and as many people as possible should watch the event.

Blackenings mostly happen in rural areas of north-east Scotland, the Highlands, and the Northern Isles. The origins of this tradition are unclear, but Dr. Sheila Young, a researcher from the Elphinstone Institute at the University of Aberdeen, has shown that it developed from an older Scottish ritual called feet-washing. It is uncertain exactly when the custom began, but it likely started as a serious washing ceremony for both men and women on the night before their wedding. By the early 19th century, the feet and legs were covered in black substances.

Later, the ritual became more playful, with the legs and feet being alternately blackened and cleaned. By the late 19th and early 20th centuries, elements like chasing, capturing, and publicly displaying the couple became part of the tradition. This change required the ritual to take place outdoors, which happened around the same time more people began getting married in the summer.

The tradition began as a washing ceremony but later became a messy one. It is likely that a change in how the ritual was performed led to its new name. While the blackening has Scottish roots, a similar practice called a "doing" also exists in Northern Ireland.