Line dance is a formation dance where a group of people stand in a line or in lines, and they all execute the same dance moves. In a smaller group there may be only one line, but usually there are several parallel lines, one behind the other. A dance teacher, or more experienced dancer, will usually perform in the center of the first line. Inexperienced dancers are encouraged to take positions in the middle of the group to allow watching the person's feet in front of them on all four walls. Experienced dancers are encouraged to take positions on the outside edges of the group to help others.

In this parallel lines formation the dancers dance in a synchronized manner, but independently of each other. There are usually no moves that require any interaction between the dancers, other than they execute the maneuvers at the same time.

There are, however, several variations to this parallel lines set-up. There may, for example, be two set of lines where the dancers face in directly towards each other. In larger groups these will become several sets of in-facing parallel lines. In these "contra" line dances, the dancers will dance with the others in the facing lines. The dancers often weave in and out, exchanging places, or dance up to each other, and make momentary contact, such as a hand clap, or a swing, or take hold in Promenade position for a few counts, and then move on.

These contact maneuvers are more likely in the variation where line dancing takes place in two concentric rings which are facing each other, such as Wild Wild West or Circle Jerk.

In the early to mid 1990's, and before, line dance had a cowboy image, and it was danced predominately to country-western music. This has been changing since the late 1990's, as more young people became involved. Today, Country music may make up the minority of a DJ's play list, with the balance spread through many different musical styles, including Celtic, Swing, Pop, Rock, Big Band, Folk, and almost anything else that has a regular beat.

Line dance is popularly thought of as originating in the Wild West. In fact, its roots go back far in history. Folk dances, including the "Virginia Reel", are danced in line formation. There have been line dances during the heyday of many modern popular music styles, including swing, rock and roll, and disco.

Line dancing's current popularity grew out of the disco period, when the country-western dance and music communities continued to explore and develop this form of dancing.

Billy Ray Cyrus' 1992 hit Achy Breaky Heart, helped catapult western line dancing back into the musical mainstream's public consciousness, and in 1998, manufactured band Steps created further interest with the song 5678. Line dancing is a popular recreation activity and is practiced and learned in country-western dance bars, social clubs, dance clubs and ballrooms worldwide. It avoids the problem of imbalance of male/female partners that plagues ballroom/swing/salsa dancing clubs. It is sometimes combined on dance programs with other forms of country-western dance, such as two-step, shuffle, western promenade dances, as well as western-style variants of the waltz, polka and swing.

Line dances can be seen in films such as Saturday Night Fever, Hairspray and Urban Cowboy.