Firefighters spent three and a half hours tackling a blaze which broke out on the roof of the iconic landmark.
A number of people had been held in a “safe area” at the top of the building while the rest of the tower was evacuated, according to Lancashire Fire Service.
There are no reported injuries.
Firefighters were called to reports of a fire on the roof of one of the tower buildings at 12.39pm. It was put out at approximately 4pm.
The people at the top of the tower were allowed down once the emergency services had finished checks to confirm it was safe to move them.
Emergency services will maintain a presence at the site into the evening.
“Firefighters will remain at the scene for the next few hours to damp down and begin the fire investigation,” Lancashire Fire Service said.
Six crews of firefighters wearing breathing apparatus fought to extinguish the fire using two hose reels.
Four fire engines and an aerial ladder platform attended the scene.
The fire broke out on the fifth floor of the building, where the popular vantage points of the Blackpool Tower Eye and the Sea View Terrace are located.
The historic ballroom, which hosts shows of the hit BBC programme Strictly Come Dancing, was not damaged.
Crowd control measures are in place and Bank Hey street has been closed by the police as a result of the incident.
Blackpool Tower is an observation tower and an entertainment complex, a three-storey block which features an aquarium and cafeteria, Tower Circus, the Tower Ballroom and roof gardens.
More from UK
LIVE: Do we have equality in the UK? #100Women
Feminism has gone far enough, most Britons say
LIVE: Police to update on ex-spy ‘poisoning’
Jeremy Corbyn accuses UK troops of ‘directing’ Yemen war as Saudi Crown Prince visits
Two lorry drivers facing jail over M1 crash which killed eight people
Britain First leaders Paul Golding and Jayda Fransen found guilty of harassment
The base of the tower sits within the complex.
The Victorian attraction was designated a Grade I listed building in 1973. It is the 120th tallest freestanding tower in the world.