Dia Mirza was born in Hyderabad, Andhra Pradesh. Her father, Frank Handrich, was a German graphic and industrial fair designer, architect, artist and interior designer from Munich and her mother, Deepa is a Bengali Hindu who is an interior designer, landscaper and currently does social work as a volunteer to help alcoholics and addicts. They separated when she was six years old and her mother married Ahmed Mirza, who died in 2004.
Dia Mirza was a second runner up at Femina Miss India, 2000 and was subsequently sent to Miss Asia Pacific, where she won. Dia made her cinematic debut with Rehnaa Hai Terre Dil Mein opposite R. Madhavan. Although the film was not a box office success, she appeared in Parineeta, a Vidhu Vinod Chopra production