Pernilla Allwin is a Swedish actress primarily known for her early career. She achieved international fame for her role in Ingmar Bergman's masterpiece, *Fanny and Alexander* (1982).

In the film, she played Fanny Ekdahl, the co-protagonist alongside Bertil Guve (who played Alexander). Her performance, as a child actress at the time, was praised for its naturalness and emotional intensity, authentically expressing innocence and resilience in the face of adversity. Her style was distinguished by a remarkable authenticity in the portrayal of complex child roles.

Although her film career was brief, limited to a few subsequent and minor roles, her contribution to *Fanny and Alexander* remains iconic in film history.