Old school hip hop (occasionally referred to as Old Skool) describes the earliest commercially recorded hip hop music (1979–1984), and by extension the music in the period preceding it (see Roots balls hip hop). The image, styles and sounds of the old school were exemplified by figures like Run-D.M.C., Kool Herc, Afrika Bambaataa, The Sugarhill Gang, The Treacherous Three, Funky Four Plus One, Fab 5 Freddy and Grandmaster Flash and the Furious Five. This was later sent into decline with the advent of new school acts the Fat Boys and LL Cool J, with these latter acts now themselves often considered old school as we move further away in time from their initial impact.

Hip hop music began in the early 1970s in New York City with the advent of breakbeat DJing. Kool DJ Herc, Grandmaster Flash, Afrika Bambaataa and other DJs extended the breaks (short percussion interludes) of funk records. This use of extended percussion breaks led to the development of mixing and scratching techniques. As hip hop's popularity grew, performers began speaking while the music played, and became known as MCs or emcees. Melle Mel, a rapper in the group Grandmaster Flash & The Furious Five was the first to call himself "MC". Performers often emceed for hours at a time, with some improvisation and a simple four-count beat and basic chorus. MCs grew more varied in their vocal and rhythmic approach, incorporating brief rhymes, often with a theme. These early raps had precursors and parallels in other aspects of African American culture, such as the dozens and signifying. During this early stage were prominent rap groups such as Funky Four Plus One, who performed "That's the Joint" on Saturday Night Live in 1981.

The first steps towards the commercialization of hip hop came with the release of what are usually called the first two commercially issued hip hop recordings: "King Tim III (Personality Jock)" by the Fatback Band, and "Rapper's Delight" by The Sugarhill Gang. "King Tim III" is considered technically the earliest recorded hip hop song: this is however a contentious statement as there were numerous tracks released in 1978 and 1979 by various artists. It was the Sugarhill Gang that won hip hop its first mainstream popularity. Though neither the Fatback Band nor the Sugarhill Gang had significant roots in the DJ culture, "Rapper's Delight" became a Top 40 hit on the U.S. Billboard pop singles chart. After the releases of follow ups by acts such as Kurtis Blow ("The Breaks"), The Sequence ("Funk You Up"), and Grandmaster Flash & the Furious Five ("Freedom"), hip hop was pegged as a successful, yet temporary, trend in music. Later in 1981, Blondie released their hit single "Rapture" which helped to bring hip hop to a wider audience. At that time, the hip hop culture also received attention from the media, as exemplified in such films as Wild Style (1982), Style Wars (1983) and Beat Street (1984).

Old school hip hop would often sample disco and funk tracks such as "Good Times" by Chic. However the use of funk samples went into a decline from 1983 onwards. A live band was often used, as in the case of The Sugarhill Gang. The use of extended percussion breaks led to the development of mixing and scratching techniques. Scratching was pioneered by Grand Wizard Theodore in 1977, and the technique was further developed by other prominent DJs such as Grandmaster Flash. One example includes Grandmaster Flash's "Adventures on the Wheels of Steel", which was composed entirely from sampled tracks. However very few tracks contained significant scratching techniques prior to 1981. In contrast with the later rhymes of new school hip hop, old school rap was relatively simple in its rhythms and cadences.

Old school rap was often focused on good times, parties and friendship. An exception was the socially orientated song "The Message", which was written by Melle Mel for his hip hop group, Grandmaster Flash and The Furious Five. The popularity of "The Message" led conscious rap to gain a place in the hip hop canon.

During the 1980s, hip hop began to diversify and develop. From the mid 1980s, gangsta rap became prominent in the West Coast and East Coast, with groups such as N.W.A and Public Enemy. Hip hop also fused with elements of electro, pioneered by the work of Afrika Bambaataa. Some rappers even became mainstream pop performers, including Kurtis Blow, whose appearance in a Sprite commercial made him the first hip hop musician to be considered mainstream enough to represent a major product. The Fat Boys also starred in two movies, and were sponsored by Pepsi, Swatch, Louis Vuitton, and Sbarro. RUN-DMC also starred in two movies, lending a role to the fat boys in the film 'Krush Groove'.