Sophie’s father in Mamma Mia! is never definitively revealed in the movies or musical. The story presents three possible fathers: Harry Bright, Bill Anderson, and Sam Carmichael, all of whom were past lovers of Donna Sheridan, Sophie’s mother

. Here is a summary of the possibilities:

• Harry Bright : He was Donna’s first lover and a practical, sweet man. However, his relationship with Donna was brief—a one-night stand—making it statistically less likely he is Sophie's father

• Bill Anderson : Bill has a strong connection to Donna, as his great-aunt Sophia left money to Donna to start her hotel. Sophie shares adventurous traits and humor with Bill, and actress Amanda Seyfried (who plays Sophie) has expressed a personal hope that Bill is the father, citing a touching scene between Sophie and Bill as evidence

• Sam Carmichael : Sam spent the most time with Donna, suggesting a higher probability of being Sophie's biological dad. A theory highlights that Sophie shares Sam’s artistic talent, which Donna does not display, supporting the idea that Sam could be the father

Ultimately, the story emphasizes that Sophie considers all three men as father figures, and the mystery remains unresolved by design. The narrative suggests that biology is less important than love and family bonds

. In conclusion, while fans and theories lean toward Bill or Sam as the most likely biological fathers, Mamma Mia! leaves the question open, making all three men Sophie's dads in a meaningful sense.