Stephen Streater was born in Boston Lying-In Hospital, Massachusetts, United States. He achieved a degree in mathematics from Trinity College, Cambridge and then began a PhD on artificial pattern recognition in the physics department at King's College London.
Streater is married to Victoria Jane née Fantl and has a daughter (Sophie). He has a sister (Catherine) and a brother (Alexander). His hobbies include playing classical chamber and orchestral music, Go, new technology, and making videos. Streater's father, Ray Streater, is a professor of mathematics at King's College London.