A group of Year 12s at a northern suburbs high school posted on Facebook that a female teacher should be raped and murdered, prompting Education Department director-general Sharyn O'Neill to warn students and parents to show respect for teachers.
Six students were suspended from Ballajura Community College for writing the derogatory and sexually suggestive comments about the teacher online.
The department confirmed that some of the remarks referred to rape and murder.
Ballajura acting principal Cheryl Townsend said the comments appeared on three private Facebook profiles two weeks ago.
"This type of online abuse is absolutely unacceptable," she said.
"As soon as this was brought to our attention, we acted quickly to discipline the students and meet their parents."
Ms Townsend said the school and community had offered support to the teacher, who had decided not to report the matter to police.
The students, who expressed regret for their actions, were suspended for between one and five days depending on the nature of what they wrote.
They were also banned from taking part in a river cruise, a Year 12 fun day and from attending the final Year 12 assembly.
Ms O'Neill said she supported the school's strong stance.
"We expect better behaviour and more respect from our students towards teachers and school staff," she said.
"This sends a clear message to students and parents everywhere that you cannot hide behind faceless Facebook and you must show respect to teachers."
Education Minister Peter Collier said Commonwealth laws allowed Federal and State police to investigate online threats.
"The bullying of school students and staff by any means is simply unacceptable," he said.
"Unfortunately, the advent of social media such as Facebook has provided bullies with an additional vehicle for intimidation.
"As with any form of bullying, this will not be tolerated in our schools."
Shadow education minister Paul Papalia said online abuse was a serious issue and he was not convinced that suspending individual students would send a strong enough message.
He said Labor was proposing a new State law to deal with cyber bullying.
WA Secondary School Executives Association president Rob Nairn said students often made inappropriate remarks on social media without thinking through the consequences.
He said highly abusive comments should not be tolerated
"I don't believe these types of comments would be suitable for anybody, whether they are a teacher or anyone else," Mr Nairn said.
WA Primary Principals Association president Stephen Breen said the notion of respect had dwindled in society in recent years, which had filtered into schools.
"In primary schools, we spend a lot of our time and resources on the development of the social skills of children," he said.