Biology teacher Gavin Atkins has been removed from his post at Castlebrae High School in Edinburgh pending the result of a probe into claims he engaged in sexual activity with a female adult learner.
It is understood he was suspended for an alleged breach of professional standards and is not accused of any criminal wrong-doing, although a police investigation is said to be ongoing.
The news comes days after headteacher Derek Curran was removed over historic allegations of sexual impropriety with a female pupil.
Shocked parents at the school said it was vital the local authority acts quickly over the claims. Susan Heron, vice-chairwoman of the parent council, said: "The council has to get this wrapped up as soon as possible. I have grave concerns over whatever is going on having a detrimental effect to the school. We are having a meeting to discuss this."
A police investigation continues into allegations surrounding Mr Curran, who was brought in to turn around once-failing Castlebrae High's fortunes. A council spokeswoman said: "We can confirm that another member of staff is under precautionary suspension to allow a police investigation to take place."