Matthew Christopher Grau (born December 13, 2004), known professionally as Matt Ox, is an American rapper and singer from Philadelphia.

He is best known for his 2017 single "Overwhelming", and for being featured on the 2018 platinum certified track "$$$" on XXXTentacion's sophomore album ?

[4] Ox was 12 years old when he released the music video for the single "Overwhelming" in 2017 featuring instrumentals by Oogie Mane.

[4] In March 2018, he worked with rapper XXXTentacion on the song "$$$", which was featured on his sophomore album, ?.

He released his first solo extended play on February 12, 2021, a 5-track EP titled Unorthodox.