Glasgow City Chambers in George Square, the Finnieston Crane, the Ovo Hydro and Queen Elizabeth University Hospital changed colour later to raise awareness for the cause while remembering the 311 people who died of a drug related death in the city last year.
Last month, it was revealed that Glasgow had a record number of drug deaths last year and the highest number of fatalities in Scotland.
Greater Glasgow and Clyde also had the largest death rate of all health board areas with 33.7 deaths per 100,000 population between 2017-2021.
As a mark of respect, the lighting display was organised by the alcohol and drug partnership (ADP).
Jacqueline Kerr, ADP chairwoman, said: “We’re delighted so many of Glasgow’s most recognisable landmarks will be showing their support on International Overdose Awareness day.
“In Glasgow alone, we lost 311 people to drug related deaths in 2021. Every drug related death is preventable so it is vital that we all come together to reduce the harms caused by alcohol and drugs.
“We hope that lighting up buildings across the city will show support to the outstanding services and recovery communities across Glasgow but also to help raise awareness and encourage people to get involved in any way they can, for example learning to spot an overdose and carrying naloxone.”