The 2018–19 Western Illinois Leathernecks men's basketball team represented Western Illinois University during the 2018–19 NCAA Division I men's basketball season. The Leathernecks, led by fifth-year head coach Billy Wright, played their home games at Western Hall in Macomb, Illinois as members of the Summit League. They finished the season 10-21, 4–12 in Summit League play to finish in 8th place. They beat top-seeded South Dakota State in the quarterfinals of the Summit League tournament, before losing to North Dakota State in the semifinals.