They were valued at nearly twice the league average, according to the annual list published by business magazine Forbes.
The Cowboys, who have reached the playoffs only nine times since winning their last Super Bowl in 1995, are worth $US4.8 billion ($NZ5.7 billion), a 14% rise from last year, Forbes said.
Reigning Super Bowl champions New England Patriots ($NZ5.1 billion) were joined by New York Giants ($NZ4.5 billion), Washington Redskins ($NZ4.2 billion) and San Francisco 49ers ($NZ4.2 billion) in the top five.
Forbes calculated the average value of the NFL's 32 teams at $US2.52 billion, an 8% jump that was driven by hefty television contracts and new stadiums and stadium renovations that help to generate more revenue from premium seating and amenities.
The 10 most valuable NFL teams:
1. Dallas Cowboys ($US4.8 billion)
2. New England Patriots ($3.7 billion)
3. New York Giants ($3.3 billion)
4. Washington Redskins ($3.1 billion)
5. San Francisco 49ers ($3.05 billion)
6. Los Angeles Rams ($3 billion)
7. Chicago Bears ($2.85 billion)
8. Houston Texans ($2.80 billion)
9. New York Jets ($2.75 billion)
10. Philadelphia Eagles ($2.65 billion)
