Mavalvala was born in Lahore, but primarily raised in Karachi, Pakistan. She attended the Convent of Jesus and Mary, Karachi, where she received her O-Level and A-Level qualifications. She moved to the United States in 1986 and enrolled at Wellesley College, where she received a bachelor's degree in physics and astronomy in 1990. She then joined Rainer Weiss 's group in the MIT physics department and received her PhD in 1997. Born to a Parsi family that practiced Zoroastrianism, Mavalvala was the younger of the two children.