Holy Rood RC school in Edinburgh has launched an internal probe after claims a teacher let pupils use the 'N-word' in class.
The claims were published in an open letter on the school's Twitter page.
The note also claims that one teacher told pupils to “go back to your own country” during a lesson.
It adds: “We are not doing this to insult or belittle the school, we are just hoping that you do more to protect people of colour in Holy Rood, including firing racist teachers.
“Holy Rood High School needs a change and we’re not going to keep letting you be silent. Everyone needs to be held accountable.”
An Edinburgh Council spokesman said: “The school treats allegations of racism very seriously and in line with the authority’s equalities policy.
“The letter on our Twitter page contained serious allegations which are being investigated.
“We continue to recognise, respect and celebrate the religious, cultural and social diversity with the Holy Rood community.
“We are committed to promoting equality and strive to achieve this through our school values.”
