The Religious Studies department at Watford Grammar School for Girls has achieved the Gold Quality Mark, awarded to schools nationally for maintaining excellent standards in Religious Education.
Teachers were congratulated on their outstanding academic results at GCSE and Advanced Level, and for the high quality of the teaching and learning in the subject.
Only two other schools in England have reached this standard in 2014, and WGGS was the only one in Hertfordshire.
Headmistress Dame Helen Hyde said: "To achieve the Gold Standard, the RS Department has to promote the subject in school and beyond in the wider community. I am particularly pleased that we are a Beacon School for Holocaust Studies."
The Gold Award certificate has taken pride of place on the WGGS honours board.