Gordon Lane, which runs from opposite The Lighthouse in Mitchell Street to Gordon Street, is described as a crime hot spot.
The lane provides access to the rear of shops in Gordon Street, Buchanan Street, Mitchell Street and Mitchell Lane.
It was also decided to use the lane for refuse bins from premises at Royal Exchange Square and Exchange Place to get them off the Style Mile.
But the lane is increasingly being used by drug dealers, drunks and criminals.
Police figures show there have been a "significant" number of crimes in the lane over the past year.
These include the sexual assault of a young woman, theft, possession of drugs, urinating, threatening and abusive behaviour and drinking alcohol.
The area, just yards from Glasgow's top shopping street, is also used by people sleeping rough.
A number of organisations have raised concerns about the problem, including police, Glasgow Chamber Of Commerce, businesses and the Style Mile steering group.
In an attempt to solve the problem, city councillors have agreed gates will be fitted to both ends of the privately owned lane.
Robert Brown, executive director of development and regeneration, said: "Glasgow Community and Safety services is of the opinion the lane is unsafe for general public use and have investigated several means of improving its safety, including improving lighting in the lane and installing CCTV cameras.
"They have concluded these measures might reduce superficial issues in the lane, but are unlikely to succeed in removing the fundamental issues and preventing criminal activity."
Once the gates are installed, companies will be able to get access by using a keypad. There will also be access for the emergency services.
Senior planner Kevin McCormack told the planning committee: "There are a number of private CCTV cameras along the lane, but police tell us CCTV helps a prosecution but it does not prevent an event happening.
"Events are so serious in this lane that a physical barrier is necessary.
"It is a known crime hotspot, so much so, police have increased their presence in this area.
"There are no store frontages in this lane, which is an area where people are undertaking criminal activity."
Anderston/City councillor Nina Baker welcomed the introduction of gates.
She said: "I am very pleased to see this happen and I hope it encourages other proprietors because some of the much longer lanes, for example at the back of Sauchiehall Street, are in a terrible state, with significant anti-social behaviour.
"I hope other building proprietors consider whether they could move forward proposals for gates of this sort.
"One of the reasons these lanes are dangerous is because people are using them for urination because of the lack of late night toilets once they leave pubs or clubs.
"I don't think there is enough provision and men and women have to dodge down one of these lanes."
Sex crimes in other lanes in the area have also caused concern.
In January last year, a woman in her early 20s was dragged into McCormick Lane, near Buchanan Street, and sexually assaulted.
After the first attacker left, a second man went into the lane and carried out a second attack.
In April this year, a 40-year-old woman told a jury she was raped after being dragged into a city lane after a night out with friends.
And in August, a woman was sexually assaulted in a lane leading to Buchanan Street.