A Network Rail spokesperson said the station will not reopen on Monday morning “following a fire at a vape shop on Union Street this afternoon”.
Police have also cordoned off the street between Gordon Street and St Vincent Street. Diversions have been put in place.
People have been urged to avoid the area and police have advised residents to keep their windows closed.
In a statement issued at 19:45 local time, a Scottish Fire and Rescue Service spokesperson said: “More than 60 firefighters are currently working to tackle a large building fire on Union Street, Glasgow.
“We were alerted at 15:46 on Sunday, 8 March, to reports of a fire affecting the ground floor of a four-storey commercial building.
“At its height, 12 fire appliances and three high-reach vehicles were mobilised to the area, where firefighters are currently working to extinguish the fire.
“There are no reported casualties, and crews remain at the scene.”