Police and fire crews were called to the blaze on Helen Street at about 4:30pm.
The fire ripped through Japanese Autoparts near Ibrox Stadium, sources said.
A total of nine appliances were sent to the scene. Fire chiefs said a number of tyres and vehicles within the scrap yard had caught fire. No injuries were reported as of this morning.
SP Energy Networks reported a power cut in the Govan area due to the incident, with engineers restoring power supplies to local residents around 9pm last night.
The billowing black smoke could be seen right across Glasgow.
Dramatic pictures were posted by residents on social media.
A Scottish Fire and Rescue spokeswoman said last night: “Around 50 firefighters are currently tackling a blaze at a Glasgow scrapyard. A total of nine appliances, a high volume pump and a forward control unit have been mobilised to the city’s Helen Street.
“The Scottish Fire and Rescue Service crews are presently working to contain the fire which has affected large quantities of tyres and a number of vehicles.”
One eye witness said: “The fire was visible from around the southside of Glasgow but as far as Greenock the plume could be seen.
“The fire was rampant when I first arrived, I could see the smoke swirling and flames from the base of the plume. A lot of people had gathered around but no one knew exactly what was going on or what was on fire, there was a distant smell from the blaze but it wasn’t pungent or overly strong despite the black flames.
“There was continuing bangs and what sounded like the crunching and collapsing of metal as the fire continued to grow. The blaze moved from the base to the left and right of the building. A number of people had gathered to watch it and sirens and police lights could be seen as they tried to close the road and fight the blaze.
“Some people were covering their mouth in case the air was toxic with the smoke. There were sparks flying as well as loud bangs and everyone kept debating what was in the building.”
A spokesman for Police Scotland advised this morning that the blaze was now under control and that fire service personnel would remain at the scene for some time ‘damping down’.