Old school hip hop (also spelled "old skool") describes the earliest commercially recorded hip hop music (approximately from 19791984), and the music in the period preceding it from which it was directly descended (see Roots of hip hop). Old school hip hop is said to end around 1983 or 1984 with the emergence of RunD.M.C., the first new school hip hop group. However, some old school rap stations cover 1980s hip hop in general, occasionally extending even into the mid 1990s. The image, styles and sounds of the old school were exemplified by figures like Afrika Bambaataa, The Sugarhill Gang, Spoonie Gee, Treacherous Three, Funky Four Plus One, Kurtis Blow, Fab Five Freddy, Busy Bee Starski, Lovebug Starski, Doug E. Fresh, The Fat Boys, The Cold Crush Brothers and Grandmaster Flash and the Furious Five, and it is characterized by the simpler rapping techniques of the time and the general focus on party related subject matter.

Old school hip hop is noted for its relatively simple rapping techniques compared to later hip-hop music. Artists such as Melle Mel would use relatively few syllables per bar of music, with relatively simple rhythms. Much of the subject matter of old school hip hop centers around partying and having a good time. One notable exception is the song "The Message", which was written by Melle Mel for his hip hop group, Grandmaster Flash and The Furious Five. Immortal Technique explains how party content played a big part in old school hip hop, in the book How to Rap: "hip-hop was born in an era of social turmoil... in the same way that slaves used to sing songs on a plantation... that's the party songs that we used to have". Battle rap was also a part of old school hip hop. Talking about battle rapping, Esoteric says, "a lot of my stuff stems from old school hip-hop, braggadocio ethic". A famous old school hip hop battle occurred in December 1981 when Kool Moe Dee challenged Busy Bee Starski. Busy Bee Starski's defeat by the more complex raps of Kool Moe Dee meant that "no longer was an MC just a crowd-pleasing comedian with a slick tongue; he was a commentator and a storyteller", which KRS-One also credits as creating a shift in rapping in the documentary Beef.

Freestyle rap during hip-hop's old school had a different definition from the definition it has today - Kool Moe Dee refers to this earlier definition in his book, There's A God On The Mic: "There are two types of freestyle. Theres an old-school freestyle thats basically rhymes that youve written that may not have anything to do with any subject or that goes all over the place. Then theres freestyle where you come off the top of the head". In old school hip hop, Kool Moe Dee says that improvisational rapping was instead called coming off the top of the head, and he refers to this as the real old-school freestyle. This is in contrast to the more recent definition defining freestyle rap as "improvisational rap like a jazz solo". 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 Flash on the turntables. However very few tracks contained significant scratching techniques prior to 1981. Uncle Louie of Uncle Louie Music Group is considered the CEO of Old School Hip Hop.