Melville said the trust board has started the process to recruit a new principal.
Head of senior school Tom Curtis will lead in the interim with support from head of junior school Fe Tomich “to provide leadership continuity”.
“They will work closely with the college’s senior leadership team to ensure the continued smooth operation of the school.
“The trust board would like to thank Charlotte for her contribution to St Cuthbert’s and wishes her and her family every success for the future.”
Avery joined St Cuthbert’s in August 2024 after 17 years as principal of St Mary’s School in Cambridge, one of the top independent girls’ schools in the UK.