Bryant, 41, and his 13-year-old daughter Gianna died following a helicopter crash in Calabasas, California on Sunday, NBA commissioner Adam Silver confirmed.
Five-time NBA champion Bryant transcended basketball after his selection in the 1996 draft, going on to spend his entire 20-year career with the Lakers.
Football superstar and six-time Ballon d'Or winner Messi joined the list of mourners, using Instagram to write: "I have no words… all my love for Kobe's family and friends.
"It was a pleasure to meet you and share good times together. You were a genius like few others."
Bryant was the face of the Lakers, even after his retirement in 2016.
The guard earned MVP honours in 2008, while he was named the Most Valuable Player in the 2009 and 2010 NBA Finals.
Bryant was also an 18-time All-Star to go with numerous other accolades, including two Olympic Games gold medals with the United States.