Trap music, also known simply as trap, is a subgenre of hip-hop music that originated in the Southern United States, with lyrical references to trap starting in 1991 but the modern sound of trap appearing in 1999. The genre gets its name from the Atlanta slang term "trap house", a house used exclusively to sell drugs. Trap music is known for its simple, rhythmic, minimalistic productions that use synthesized drums, and is characterized by complex hi-hat patterns, snare drums, bass drums, some tuned with a long decay to emit a bass frequency (originally from the Roland TR-808 drum machine), and lyrical content that often focuses on drug use and urban violence.

Pioneers of the genre include producers DJ Spanish Fly, DJ Paul & Juicy J, Kurtis Mantronik, Mannie Fresh, Shawty Redd, Fatboi, Zaytoven, DJ Screw, and DJ Toomp, along with rappers T.I., Jeezy, and Gucci Mane. The style was popularized by producer Lex Luger, who produced the influential Waka Flocka Flame album Flockaveli in 2010, and cofounded the prolific hip-hop production team 808 Mafia.

Since crossing over into the mainstream in the 2010s, trap has become one of the most popular forms of American music, consistently dominating the Billboard Hot 100 throughout the decade, with artists such as Drake, Kendrick Lamar, Future, Playboi Carti, 21 Savage, Migos, Lil Uzi Vert, Post Malone, XXXTentacion, DaBaby, Roddy Ricch, Young Thug, and Travis Scott (among many others) all achieving No. 1s on the chart with songs featuring production inspired by the trap subgenre. It has influenced pop and R&B artists including Ariana Grande, Beyoncé, Miley Cyrus, Rihanna, the Weeknd and Sabrina Carpenter. Its influence can also be heard in reggaetón and K-pop. In 2018, hip-hop became the most popular form of music for the first time ever (according to Nielsen Data), coinciding with trap's continued rise in popularity. 2019 saw trap-influenced hits amass high commercial success such as Ariana Grande's "7 Rings" spending eight weeks at No. 1 on the Billboard Hot 100 chart and the country-trap song "Old Town Road" by Lil Nas X (featuring Billy Ray Cyrus), which broke the record for spending the most weeks (19) on top of the Billboard Hot 100 chart, as well as becoming the fastest song to reach a Diamond Certification.

In trap music, lyrical themes mostly revolve around the general life and culture in the "trap" or in the actual southern trap house where controlled substances are being sold. The term "trap" refers to places where drug deals take place. Other topics also include street life, acquiring wealth, violence, American vehicles, and life experiences that artists have faced in their southern American surroundings.

Trap music employs multilayered thin- or thick-textured monophonic drones with sometimes a melodic accompaniment expressed with synthesizers; crisp, grimy, and rhythmic snares, deep 808 kick drums, double-time, triple-time, and similarly divided hi-hats, and a cinematic and symphonic use of synthesized string, brass, woodwind, and keyboard instruments to create an energetic, hard-hitting, deep, and variant atmosphere. These primary characteristics, the signature sound of trap music was pioneered and originated by Shawty Redd's minimalist, horror-inspired style and DJ Toomp's melodic, sample-driven approach, drawing inspiration from jazz, soul, R&B, gospel, and funk. Trap may use a range of tempos (often programmed in half-time to achieve finer hi-hat subdivisions) from 50 (100) BPM to 88 (176) BPM, but the tempo of a typical trap beat is around 70 (140) BPM.

As hip hop grew, it created many forms such as gangsta rap, which shone more of a light on the dangerous lifestyle of those in impoverished American neighborhoods, and on political issues. As hip hop mutated into 'gangsta' rap, 'gangsta' rap would then transform to trap, a new form of music, that followed a different thought process and different tones. Early producers creating trap music included Lil Jon from Atlanta, Georgia, where the term originated as a reference to places where drug deals are made.^{[citation needed]}

Lil Jon, along with Mannie Fresh from New Orleans and DJ Paul & Juicy J from Memphis, Tennessee worked with local acts in Atlanta including Dungeon Family, Outkast, Goodie Mob, and Ghetto Mafia. In 1992, one of the earliest records to release was UGK's "Cocaine In The Back of the Ride" from their debut EP, "The Southern Way". Later in 1992, they released the popular "Pocket Full of Stones" from their major-label debut album Too Hard to Swallow. It was also featured in the 1993 film Menace II Society. In 1996, Master P released his single "Mr. Ice Cream Man" from his fifth studio album Ice Cream Man. Fans and critics started to refer to rappers whose primary lyrical topic was drug dealing as "trap rappers". T.I.'s 2001 song "Dope Boyz", from his debut album I'm Serious, includes the lyrics "the dope boyz in the trap nigga / the thug nigga, drug dealer where you at". David Drake of Complex wrote that "the trap in the early 2000s wasn't a genre, it was a real place", and the term was later adopted to describe the "music made about that place".

During the early- to mid-2000s, trap music began to emerge as a recognized genre after the mainstream success of a number of albums and singles with lyrics that covered life in "the trap", drug dealing and the struggle for success. Several Southern rappers with drug dealer personas such as T.I., Young Jeezy, Gucci Mane, Boosie Badazz, Young Dolph, Lil Wayne, and Rick Ross produced crossover hits and helped expand the popularity of the genre, with trap records beginning to appear more heavily on mixtapes and radio stations outside of the South. Though trap artists were somewhat diverse in their production styles, the signature and quintessential trap sound (typically based around synth, orchestra, and string swells with tight, bass-heavy 808 kick drums) that would come to be associated with the genre developed in Atlanta during trap's mid-2000s breakthrough. Some of the notable trap producers during the mid to late 2000s include DJ Toomp, Fatboi, Drumma Boy, Shawty Redd, D. Rich, and Zaytoven. The first wave of the trap sound was influenced by earlier Southern producers such as Lil Jon, Mannie Fresh, and DJ Paul.