Five-pin billiards or simply five-pins or 5-pins (Italian: [biliardo dei] cinque birilli; Spanish: [billar de] cinco quillas or casín), is today usually a carom billiards form of cue sport, though sometimes still played on a pocket table. In addition to the customary three balls of most carom games, it makes use of a set of five upright pins (skittles) arranged in a "+" pattern at the center of the table. The game is popular especially in Italy, but also in some other parts of Latin America and Europe, with international, televised professional tournaments (for the carom version only). It is sometimes referred to as Italian five-pins or Italian billiards (Italian: biliardo all'italiana), or as simply italiana (in Italian and Spanish). A variant of the game, goriziana or nine-pins, adds additional skittles to the formation. A related pocket game, with larger pins, is played in Scandinavia and is referred to in English as Danish pin billiards, with a Swedish variant that has some rules more similar to the Italian game.

Until the late 1980s, the game (with some rules differences) was a form of pocket billiards, known in English as Italian skittle pool, and was principally played in pubs, with an object ball that was smaller than the two cue balls. Professional and regulated amateur play today exclusively uses pocketless tables and equal-sized balls. Professional competition began in 1965, and play is centered in billiard parlors, with players competing in provincial, regional, and national federations. The pocket version is still favored by some in amateur play.

The regulation game is played on a normal 5 by 10 ft (1.5 by 3.0 m) pocketless carom billiards table, with standardized playing surface dimensions of 1.42 by 2.84 m (approximately 4-2/3 by 9-1/3 ft), plus/minus 5 mm (approx. 0.2 in), from cushion to cushion. The slate bed of the table must be heated to about 5 degrees C (9 degrees F) above room temperature, which helps to keep moisture out of the cloth to aid the balls rolling and rebounding in a consistent manner, and generally makes the table play "faster". In informal play, an unheated table is often used.

Like most other carom games, five-pins requires three standard carom billiard balls of equal diameter: a cue ball for the first player, typically plain white, another cue ball for the second player, historically white with a spot but now typically yellow, and a red object ball,. The balls are 61.5 millimetres (2.42 in) in diameter and weigh between 205 and 220 g (7.2 and 7.8 oz); 7.5 oz is average). The white cue ball is given to the starting player, who may place it anywhere on the head side of the table (without disturbing the pins)—i.e., anywhere unobstructed between the head rail and the center string. The red object ball is placed at the foot spot (i.e., the intersection of the foot string and the long string. The yellow (or spotted white) cue ball of the opponent is placed on the long string, in a position that can be labelled the "foot rail spot", 10 cm (approx. 4 in) from the foot rail.

As the name implies, the game makes use of five upright pins called skittles in English (so-called since at least 1634), birilli (singular birillo) in Italian and quillas in Spanish, which look like miniature bowling pins, 25 mm (0.98 in) tall, and with 7 mm (0.28 in) round, flat-bottomed bases. There are traditionally four white pins, and one red. The red pin is placed on the center spot (the exact middle of the table both lengthwise and widthwise), and the four white pins are placed equidistant from the red in a square diamond pattern around it. Two whites are aligned along the center string with the head and foot spots, as well as the rail diamonds in the center of the head and foot rails, and with the red object ball, and red pin. Meanwhile, the other two whites are placed on the center string, aligned with the diamonds in the center of the long rails, and again with the red pin. The final pattern looks like a plus sign. This arrangement of pins on the table is referred to as the "castle". Tables have the precise castle positions for the pins, and for the starting positions of the balls, permanently marked, as they must be placed back into position before every shot if any have been knocked over or moved.

Each player uses a cue stick to shoot the appropriate cue ball; average cue length is 140 cm (about 55 in.) A bridge stick (rest) may be used to reach long shots.

Though there are variants in Central and South America, the Italian five-pins rules are the best codified. Because the Italian-rules championships organized by the Italian Federation of Billiard Sport (FIBiS) are international, televised events, and often hosted outside of Italy, the FIBiS rules are the global de facto standard, and have been incorporated into the rules promulgated by the Union Mondiale de Billard.

The goal of the game is to earn a required number of points, before one's opponent does, by using one's cue ball to cause the opponent's cue ball to knock over pins (and to not do so with one's own cue ball), and by contacting the red object ball with either cue ball, after one's own cue ball has contacted that of the opponent, and/or by causing the object ball to knock over pins, again after one's own cue ball has contacted that of the opponent.