The 2003–04 Lehigh Mountain Hawks men's basketball team represented Lehigh University during the 2003–04 NCAA Division I men's basketball season.

The Mountain Hawks, led by second-year head coach Billy Taylor, played their home games at Stabler Arena and were members of the Patriot League.

Following the regular season, Lehigh won the Patriot League Basketball tournament to earn the conference's automatic bid into the 2004 NCAA tournament.

This was their third NCAA Tournament appearance and first in 16 years, with the most recent trip in 1988.

16 seed in the Midwest region, they fell to fellow No.