The 1998 Legg Mason Tennis Classic was a men's tennis tournament played on outdoor hard courts in Washington, D.C., United States, that was part of the International Series Gold of the 1998 ATP Tour.

It was the twenty-ninth edition of the tournament and was held from July 20 through July, 26.

Second-seeded Andre Agassi won the singles title.

Andre Agassi defeated Scott Draper, 6–2, 6–0 Grant Stafford / Kevin Ullyett defeated Wayne Ferreira / Patrick Galbraith, 6–2, 6–4