The 17-year-old was performing with her band The Pretty Reckless when she described the Scottish audience as "the craziest crowd in the whole of England".
Audience member Paul Krane told The Daily Record: "People began to cheer as they presumed she was going to say Scotland, but when the penny dropped all you could hear was boos."
Although neither Momsen or the band appeared to notice the error at the time, she apologised via her Twitter account later in the evening.
She wrote: "Glasgow, I love you, I now HAVE to tour SCOTLAND (haha, sorry bout the slip up!) (sic)."