Lessons have been cancelled and pupils have been encouraged to go home after an incident just before 12pm.
Greater Manchester Police confirmed the college has been evacuated after a bomb threat.
They did not have any information on the nature of the threat or the reasons behind it.
Investigations are ongoing.
People are being directed away from the Deane Road car park and a police car was seen parked outside the college on Deane Road.
Bolton College principal Bill Webster said: "We were alerted to an incident at 11.47am and evacuated the campus.
"Police are here and we are waiting for them to finish their routine checks and hopefully it will be a false alarm.
"Until then this campus will be closed, and we are encouraging pupils to go home if they can because of the cold.
"If you still have stuff in the college that you need to collect, please go somewhere warm to wait until campus has reopened."