Flip-flops are a type of light sandal-like shoe, typically worn as a form of casual footwear. They consist of a flat sole held loosely on the foot by a Y-shaped strap known as a toe thong that passes between the first and second toes and around both sides of the foot. This style of footwear has been worn by people of many cultures throughout the world, originating as early as the ancient Egyptians in 1500 BC. In the United States the modern flip-flop may have had its design taken from the traditional Japanese zōri, after World War II as soldiers brought them back from Japan.

Sandals are an open type of shoe, consisting of a sole held to the wearer's foot by straps going over the instep and around the ankle. Sandals can also have a heel. While the distinction between sandals and other types of footwear can sometimes be blurry, the common understanding is that a sandal leaves all or most of the foot exposed. People may choose to wear sandals for several reasons, among them comfort in warm weather, economy, and as a fashion choice. Usually, people wear sandals in warmer climates or during warmer parts of the year in order to keep their feet cool and dry. The risk of developing athlete's foot is lower than with enclosed shoes, and the wearing of sandals may be part of the treatment regimen for such an infection.