The pair both attended Wakefield Girls' High School and live in the Walton area.
Abbey, 18, initially got three As for history, geography and business, the last of which became an A*.
Younger sister Suzie, 16, achieved a nine for her GCSE in geography, eights for history and PE, a further four grades marked at seven, and a six.
Abbey said: "Obviously it was a big challenge to overcome, the fact that I wasn't doing exams, because I worked so hard.
“The night before I was very anxious because the Government didn’t have the procedures in place.”
"I feel very relieved that it's all finished".
Nearly half of GCSE results at Wakefield Girls’ were awarded at the top levels of grade 9 and 8 and 72 per cent passed GCSEs at Grade 7 or abov,e with 100 per cent pass rate for
Headteacher, Heidi-Jayne Boyes said “These results are excellent and reflect the enormous amount of dedicated work that girls and their teachers have put in over the past two years.
"With so much recent uncertainty around the awarding of results, following what has been a difficult and unsettling year, it is important we let our students know how much we value their
"We are celebrating their unwavering commitment to study and their perseverance in pursuing success in what are, by any measure, challenging times.
"We are very pleased with our headline statistics but the most important thing is that individual girls have made excellent progress during their time at Wakefield Girls’."
Students awarded grade 9/8 are: Emily Booth-Burke, Ayushi Chaurasia, Alexandra Moll, Hannah Poulton-Haselier, Sophie Russell, Mia Sedgwick, Molly Shone and