Riddim refers to multiple genres:
1. Riddim is the Jamaican Patois pronunciation of the English word "rhythm". In the context of reggae and dancehall, it refers to the instrumental accompaniment to a song and is synonymous with the rhythm section. Jamaican music genres that use the term consist of the riddim plus the voicing (vocal part) sung by the deejay. The resulting song structure is distinctive in many ways. A given riddim, if popular, may be used in dozens—or even hundreds—of songs, not only in recordings but also in live performances.

Since the 1970s, riddims have accompanied reggae music and through the 1980s, more widely known as dancehall. As seen in dancehall music, there is a voicing part – sung by the DJ – over some riddim that has probably been widely used in many other songs. There is a unique establishment in the combination of riddims and voicing.

By 1993, Jamaica finally established a copyright act, but producers still face difficulty in establishing profit. Through proper registration, many artists now work on negotiating their royalties and taking it more seriously. The unique nature of dancehall and riddims have been highly influential on the numerous remixes that now circulate R&B and hip-hop music.

2. Riddim is a subgenre of dubstep known for its heavy use of repetitive and minimalist sub-bass and triplet percussion arrangements. It shares the same name as the Jamaican genre that influenced both it and dubstep, which originally derived from dub, reggae, and dancehall. Originating in the United Kingdom, specifically Croydon, in the early 2010s as a resurgence of the style used by early dubstep works, riddim had started to gain mainstream presence in the electronic music scene around 2015.

Despite receiving criticism for its sometimes repetitive drops, it has grown in popularity due to various well-known electronic music DJs playing songs of the subgenre in their live sets as well as various well-known electronic music artists producing the genre.