It is easy for teachers to get a reputation for being boring and straight-laced.
But these hilarious pictures prove that many actually have a wicked sense of humour.
Pupils around the world snapped pictures of the pranks, witty classroom signs and creative punishments doled out by teachers who wanted to have a little fun.
Some impressed their students by dressing up in costumes, with one history teacher posing for the yearbook in civil war uniform and another striding into the classroom as a medieval knight.
One sensitive teacher won over his class when he stepped in to help a young mother who was struggling to keep her toddler quiet.
The images were shared online and many were shared in a Bored Panda gallery. Here, FEMAIL shares some of the best examples...
Out of office: This teacher wanted to play a trick on their students during office hours
Practical joke: This teacher found a very creative way to teach one sleepy student a lesson
Telling it straight: There was no confusion over what font the children needed to use
Caught out: This teacher wanted his pupils to know that they weren't being subtle
Leading by example: This history teacher dressed up in uniform for the yearbook photo
Simple rules: This straight-talking teacher is very clear about the priorities in her classroom
Sensitive: This teacher did all he could to show his support for a young mother in his class
Special guests: A medieval knight, left, and beach babe, right, both made an appearance
Going up in flames: One teacher was keen to show this winged invader who was boss