chasuble, liturgical vestment, the outermost garment worn by Roman Catholic priests and bishops at mass and by some Anglicans and Lutherans when they celebrate the Eucharist. The chasuble is a conical or bell-shaped cloak made from a semicircular piece of cloth sewn partially up the front with an opening for the head; the related cope is not sewn in the front but closed with a clasp or brooch. In Roman Catholicism, the pope, archbishops, and some bishops wear a pallium over the chasuble as a symbol of full episcopal authority.

The chasuble developed from an outer garment worn by Greeks and Romans called the paenula or casula (“little house”) and was worn by both laity and clergy until the 6th century, eventually becoming a specifically ecclesiastical vestment. It was draped in different ways but not structurally altered until the 15th century, when the use of heavy brocades and other stiff materials led to the reduction of material over the arms until it resembled a highly decorated tabard, such as those used by knights or heralds in the Middle Ages. In the 19th and 20th centuries attempts have been made to restore the draped effect of the early chasuble, but various styles are still used.

In the Eastern churches, the equivalent vestment is the phelonion (phenolion), worn exclusively by priests.