The World Cup-winning forward was linked with a move to Old Trafford in the close-season and a possible reunion with former Bayern coach Louis van Gaal.
But, in an interview with The Guardian, Muller explained that it was never likely to happen.
"I know there was interest, but Man United were interested in a lot of players this summer," he said.
"It never really got anywhere because I had just renewed my contract [until 2019], and Bayern were clear that they saw my future here.
"The decision for me was an easy one."
As defending Bundesliga champions, Bayern have taken seven points from their opening three matches, although Pep Guardiola's men are yet to hit top form.
Some have put that down to an arduous World Cup campaign for their German contingent, but Muller is quick to dismiss that as an excuse.
"Everyone wants to link everything to the World Cup in the early weeks of the season," he said.
"You play badly: you've fallen into a hole because of the World Cup. You play well: it's the World Cup feelgood factor.
"Physically, it shouldn't be a problem at all, especially for us younger guys. Maybe in October, November, it'll become difficult, mentally. But you can't think that way when you play at Bayern. You mustn't.
"At Bayern, the journey is always headed for titles. So far, the travel agency haven't called to say there'll be complications. No rebooking, just yet."
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