The Reds boss made the declaration when asked by newspaper journalists if the team's current league position and form of local rivals Manchester City would impact on the club's standing within the game and if any of the glamour associated with United was fading.
"I don’t even need to answer it because Manchester United is not only the biggest club in the country but the biggest club in the world," Moyes responded. "To answer it, Manchester United is the biggest club.
"I don’t think any of the glamour is fading whatsoever. I think some of the results have been not what we want but I wouldn’t say the glamour is fading. I actually think the opposite."
The manager was also asked whether players were no longer viewing Old Trafford as an attractive destination, despite the club winning a record 20th league title last May.
"I don’t see it," he replied. "Not at all. Not judging by my trips and the things I’m hearing about the number of big players who want to join Manchester United.
"Maybe some players want to go for money to other clubs but, if you ask which club they want to wear the badge of, they want to wear the badge of Manchester United, because of the club’s status in world terms and everything about it."