Videos circulating on social media showed a fully-grown stag near South Craven Academy in Cross Hills, between Skipton and Keighley. The animal appeared to be in a distressed state and had an injury to its face.
A witness said staff at the secondary school were asked to close doors and windows while the male deer was at large in the grounds on Tuesday April 9.
Police were called to try and track the stag down but it had disappeared by the time they arrived on the scene. It's not known where it came from.
North Yorkshire Police said:-
"At about 10.30am on Tuesday April 9, police were called with a report that a stag, possibly in some distress, had been seen in the Cross Hills area.
"Officers from North Yorkshire Police liaised with experts from the British Deer Society. The safety and welfare of members of the public and of the animal itself were important to us, and so, as a precaution, we patrolled the area to reduce any risk to road users and pedestrians.
"However, there were no further sightings of the deer."
South Craven Academy did not respond to a request for comment.