Justin Kumi (born 16 July 2004) is an Italian footballer who plays as a midfielder for Avellino on loan from Serie A club Sassuolo. Kumi was born on 16 July 2004 in Castelfranco Veneto, Italy. He is of Ghanaian descent. As a youth player, he joined the youth academy of his hometown side in Italy. After that, he joined the youth academy of Italian side Giorgione at the age of fifteen. After that, he joined the youth academy of Italian Serie A side Sassuolo. In 2023, he received interest from Spanish La Liga side Barcelona and Dutch side PSV. He was regarded as one of the under-19 team's most important players as they won the league during the 2023/24 season. Kumi started his senior career with Italian Serie A side Sassuolo. On 28 February 2024, he debuted for the club during a 1–6 loss to Napoli. On 15 January 2025, Kumi moved on loan to Reggiana.