Issa Laye Lucas Jean Diop (born 9 January 1997) is a French professional footballer who plays as a centre-back for Premier League club Fulham.

Diop began his career at his hometown club Toulouse, making his senior debut during the 2015–16 season. He became the club's captain in 2017, before leaving for English club West Ham United in 2018, signing for a club-record fee.