The British and Irish Lions, often referred to simply as the Lions, is a rugby union team consisting of players from England, Scotland, Ireland, and Wales. The team is selected for international tours and is one of the most prestigious and recognized in the sport of rugby. The British and Irish Lions were formed in 1888, making them one of the oldest touring rugby teams. The team was originally known as the "British Isles."

Players are selected for the Lions through a rigorous process. The squad is typically chosen every four years for a major tour, often to the Southern Hemisphere. The Lions undertake tours to rugby-playing regions around the world. They have toured countries such as Australia, New Zealand, South Africa, and more. The Lions are unique in that they bring together players who are usually rivals in domestic competitions. The team represents a composite of the best players from England, Scotland, Ireland, and Wales. The team plays in distinctive red jerseys, and the selection of Lions players is considered a significant honour in a rugby player's career.

The Lions play a series of test matches against the host nation during their tours. These matches are highly competitive and are a focal point of the tour. The Lions have their own anthem called "The Power of Four," symbolizing the unity of the four nations. The Lions have had both successful and challenging tours over the years. Success is measured not only in terms of victories but also in the camaraderie and unity forged among players from different nations. Lions tours attract large numbers of supporters, known as the "Red Army," who travel to cheer for the team. The Lions have established various traditions over the years, contributing to the unique character of the team.