"Mamma Mia! flies as tuneful as a lark and as smart as a cuckoo. It offers one of those nights when you sit back and let a nutty kind of joy just sweep over you.... The true hero is British playwright Catherine Johnson, who took all these songs and cobbled a cohesive book around them. Genius."
– The New York Post
"A triumph, passionate and sharp.... The beauty of Judy Craymer's original idea and the irresistibility of Johnson's book lie in the mutual enrichment between the characters and the Abba songs. Ulvaeus's eloquent lyricism can slide by unnoticed behind Benny Andersson's infectious musical arrangements, but Johnson simply read the songs' words in order to write their innate emotional dramas seamlessly into the narrative songs and story help each other."
– The Telegraph
"The show is pleasing as it passes and it certainly features a generous swath of songs that caught the world's fancy during the '70s and '80s."
"The theatrical equivalent of comfort food."
– The New York Times
"A certified hit.... A giddy guilty pleasure."