The 56-year-old teacher was taken to hospital with a "small non-life-threatening wound to the back of her shoulder," according to a statement from Queensland Police.
Shortly before midday local time, police were called to a school in Heatley following reports that a student had stabbed a teacher.
Officers used a stun gun on the child during the incident, police said.
"Police located a 11-year-old girl inside the school grounds armed with a knife," said the statement.
Officers gave her "multiple verbal commands" before "deploying a conductive energy device," police said.
The pupil was arrested and later charged with one count each of wounding, possession of a knife in a public place or a school and threatening violence.
The girl will appear in children's court at a later date, police said.
The teacher has since been discharged from hospital, CNN affiliate 9News reported.
Senior Sergeant Scot Warrick told 9News he could not say what led to the incident.
"Right now, it's far too early for me to give any indication of what caused this," he said, adding that the event took place near a classroom.
The incident happened at Heatley Primary School in Townsville, 9News reported.
One student told the channel that he saw a girl take out a pocket knife from her bag.
"I thought it was a stick at first but then I found out it was a knife," he said.
"It looked sharp and I got scared."