Dijon Isaiah McFarlane (born June 5, 1990), known professionally as Mustard (formerly DJ Mustard), is an American record producer and DJ. A frequent collaborator of fellow California-based artists YG, Ty Dolla Sign and Kendrick Lamar, he began his career producing singles and albums for both rappers, and has since done so for other prominent acts in hip hop and R&B. He first saw recognition for his work on Tyga's 2011 single "Rack City".

Mustard's production style has been described as up-tempo and club-oriented, but also rudimentary and melodic. Most of his works begin or end with the producer tag "Mustard on the beat, hoe!"—a voice sample of YG (who says it at the end of "I'm Good", one of their early collaborations)—and include heavy use of synthesizers, claps, and frequent, reverberated use of a "hey!" voice clip. He has been credited as influential in the sound of both mainstream and West Coast hip hop productions during the early-to-mid 2010s, a style he refers to as "ratchet music".

Mustard signed with Republic Records and Roc Nation to release his debut studio album, 10 Summers (2014), which narrowly entered the Billboard 200; his second album, Cold Summer (2016), failed to chart. He then signed with Interscope Records to release his third album, Perfect Ten (2019), which peaked within the top ten of the chart and spawned the Billboard Hot 100-top 40 singles "Ballin'" (featuring Roddy Ricch) and "Pure Water" (with Migos). The success of Kendrick Lamar's 2024 single, "Not Like Us"—his first number-one production on the chart—foresaw the release of Mustard's fourth album, Faith of a Mustard Seed (2024). He founded the record label 10 Summers Records in 2014, through which he has signed musical acts including British singer Ella Mai, as well as fellow California-based artists Kiana Ledé and RJMrLA. As of 2024, he announced his upcoming fifth studio album Perfect Eleven as a sequel to his third album Perfect Ten (2019).