A soft drink (see § Terminology for other names) is a drink that usually contains water (often carbonated), a sweetener, and a natural and/or artificial flavoring. The sweetener may be a sugar, high-fructose corn syrup, fruit juice, a sugar substitute (in the case of diet drinks), or some combination of these. Soft drinks may also contain caffeine, colorings, preservatives, and/or other ingredients.

Soft drinks are called "soft" in contrast with "hard" alcoholic drinks. Small amounts of alcohol may be present in a soft drink, but the alcohol content must be less than 0.5% of the total volume of the drink in many countries and localities if the drink is to be considered non-alcoholic. Types of soft drinks include lemon-lime drinks, orange soda, cola, grape soda, ginger ale, and root beer.

Soft drinks may be served cold, over ice cubes, or at room temperature. They are available in many container formats, including cans, glass bottles, and plastic bottles. Containers come in a variety of sizes, ranging from small bottles to large multi-liter containers. Soft drinks are widely available at fast food restaurants, movie theaters, convenience stores, casual-dining restaurants, dedicated soda stores, vending machines, and bars from soda fountain machines.

Within a decade of the invention of carbonated water by Joseph Priestley in 1767, inventors in Britain and in Europe had used his concept to produce the drink in greater quantities. One such inventor, J. J. Schweppe, formed Schweppes in 1783 and selling the world's first bottled soft drink. Soft drink brands founded in the 19th century include R. White's Lemonade in 1845, Dr Pepper in 1885 and Coca-Cola in 1886. Subsequent brands include Pepsi, Irn-Bru, Sprite, Fanta, 7 Up and Campa Cola.