| Tournament details | |
|---|---|
| Country | United States |
| Final positions | |
| Champions | Los Angeles Galaxy (2nd title) |
| Runner-up | FC Dallas |
| Tournament statistics | |
| Top goal scorer(s) | Herculez Gomez Melvin Tarley (6 goals each) |
The 2005 Lamar Hunt U.S. Open Cup ran from June through September, 2005, open to all soccer teams in the United States.
The Los Angeles Galaxy won their second Open Cup championship with a 1–0 victory over FC Dallas at the Home Depot Center in Carson, California.
Although two Major League Soccer sides played in the final, the tournament featured several runs by underdogs. The Des Moines Menace of the Premier Development League beat two USL First Division teams to reach the Fourth Round. The Minnesota Thunder of the USL First Division beat three MLS teams in succession to reach the semifinals. The Rochester Raging Rhinos continued to play to record crowds and beat the MetroStars before losing in a shootout to the Chicago Fire. Four of the tournament's final 15 games went to overtime.