Stanmore twins at North London Collegiate School in Edgware gained a combined seven A-star and A grades.
Gemma and Juliette Ginsberg - who will study at Nottingham and Oxford University respectively -were up before six on results day to discover how they had fared. "We both found exams really hard, so we weren't expecting this at all," Gemma confided.
"Our mum was so happy. She kept saying: 'Four A-stars between you.'"
Although the sisters were not competitive with each other, "it's nice that we've got similar results in our final year. It's an extra-special celebration."