- Meryl Streep as Donna Sheridan, the single mother of Sophie and owner of the Villa Donna.
- Amanda Seyfried as Sophie Sheridan, Donna's daughter who is getting married and wants to find her father.
- Pierce Brosnan as Sam Carmichael, one of Sophie's potential fathers and a former lover of Donna's.
- Colin Firth as Harry Bright, another one of Sophie's potential fathers and a former lover of Donna's.
- Stellan Skarsgård as Bill Anderson, the third of Sophie's potential fathers and a former lover of Donna's.
- Dominic Cooper as Sky, Sophie's fiancé.
- Julie Walters as Rosie Mulligan, Donna's best friend.
- Christine Baranski as Tanya Chesham-Leigh, Donna's other best friend.
- Phyllida Lloyd as the director of the film.