A golf handicap is a numerical measure of a golfer's ability, or potential ability, that is used to enable players of different abilities to compete against one another. Better players are those with the lowest handicaps.

Historically, rules relating to handicaps have varied from country to country with many different systems in force around the world. Because of incompatibilities and difficulties in translating between systems, the sport's governing bodies, the USGA and The R&A, working with the various existing handicapping authorities, devised a new World Handicap System (WHS) which began to be introduced globally in 2020.

The earliest record of golf handicapping is thought to be from the late 17th century, in a diary kept by Thomas Kincaid, who was a student in Edinburgh, Scotland, although the word handicap would not come into use in golf until the late 19th century. The number of strokes to be given and the holes on which they would be in effect was negotiated between competing golfers prior to the start of play. According to The Golfer's Manual by Henry Brougham Farnie, examples of agreed terms included "third-one" (one stroke every three holes), "half-one" (one stroke every two holes), "one more" (a stroke a hole) and "two more" (two strokes a hole).

During the late 19th century, taking the difference between the average of a golfer's best three scores during the year and par became the most widely used method of handicapping in England and Scotland. As the sport grew, so did discontent with the fairness of handicapping, with less proficient players being particularly unhappy as it was much less likely for them to play to the standard of their three-score average. Another issue was the lack of consideration in the system for the varying difficulties of different courses which meant the handicap was not very portable.

In an attempt to remedy the problems with the basic handicap system and the many variations being used, the authorities in Great Britain and Ireland sought to standardize. One of the first standard and equitable handicap systems was introduced by the Ladies Golf Union (LGU) in the 1890s. This was largely achieved by means of union-assigned course ratings, instead of clubs using their own. It was not until the formation of the British Golf Unions Joint Advisory Committee in 1924 that the men's game fully coordinated to create an equitable handicap system, that included a uniform course rating, throughout Great Britain and Ireland; the Standard Scratch Score and Handicapping Scheme was introduced in 1926.

In the United States, there was a single authority governing the sport, the USGA, which made moving to a single standard handicapping scheme somewhat easier. Introduced in 1911, the first national handicap system was based on the British three-score average system. The biggest development was a "par rating" system that assessed the average good score of a scratch golfer on every course, which made the handicap more portable. It also made clear that a player's handicap was intended to reflect their potential rather than average play. Having initially allowed clubs to determine their own par ratings, the USGA quickly changed their minds and began assigning ratings. The USGA Handicap System has further developed through the years, with an increase in the number of scores used for handicap calculations, the introduction of Equitable Stroke Control, and improvements to the course rating system. However, the most significant change was the creation of the slope rating system, which enabled handicaps to account for differences in difficulty between scratch and bogey golfers. USGA Course and Slope Ratings now form the basis of many other handicap systems.

As the sport grew globally, associations around the world each created or adapted their own rules relating to handicaps. By the early 21st century, there were six major recognized handicapping systems in operation around the world: USGA Handicap System, EGA Handicap System, CONGU Unified Handicap System, Golf Australia Handicap System, South African Handicap System, and Argentinian Handicap System. While these systems share some common features, e.g. most use a common course rating system, they are not easily portable because their differences create difficulties in converting handicaps between systems. In order to eliminate these problems the USGA and The R&A, working with the various existing handicapping authorities, devised a new World Handicap System which was phased in globally in 2020.

Amateur golfers who are members of golf clubs are generally eligible for official handicaps on payment of the prevailing regional and national association annual fees. Official handicaps are administered by golf clubs with the associations often providing additional peer reviewing for low handicaps. Other systems, often free of charge, are available to golfers who are ineligible for official handicaps. Handicap systems are not generally used in professional golf. A golfer whose handicap is zero is referred to as a scratch golfer, and one whose handicap is approximately 18 as a bogey golfer.