The Gorbals Rose War Memorial was erected in honour of one-time local resident James Stokes, who was killed in action in the Second World War and who was awarded the Victoria Cross.
In the night-time incident – just 100 yards from Gorbals police station – the heartless culprits left the 10ft bronze rose bent and stole the head.
Police are as yet unsure whether the motive was vandalism or metal theft.
The Old Burial Ground and the Gorbals Rose Garden in Old Rutherglen Road is a focal point of the community and an area popular with dog walkers.
The memorial was created in 2005 by the Gorbals Art Project, which is a locally based group which works in partnership with the community to create artwork and promote regeneration.
Elizabeth Peden, from the project, created the memorial with the help of local schools.
She said: "I just feel really disappointed - we don't know if it was vandals or if it was thieves who have stolen the metal for scrap.
"I'm distraught because James Stokes' relatives still visit the memorial from time to time to lay wreaths. I felt really down about it because you do take it more personally when you have been involved in its creation.
"However, most of my concern is for the family and the primary school children who visit it to learn about history.
"I stay in the area and everyone I know is outraged by this action."
Local resident, Connor O'Brien, 20, uses the memorial's surrounding park to walk his dog, Charlie.
Connor said: "Everywhere you look there's vandalism.
"People don't have any respect for things like this, especially for people who have died in the war.
"If it was vandals, I think it's mostly caused by boredom as there's nothing to do around here."
The granite base of the memorial was made in the shape of the Victoria Cross, which is the highest award given to UK forces for valour 'in the face of the enemy'.
James' heroics have been featured in the Victor comic.
The Rose itself was made of bronze and was set to bow its head in a mark of respect for those who have given their lives in conflict.
The memorial has been on the receiving end of thugs' treatment before when, soon after being erected seven years ago, it was a target for vandals.
Ms Peden, who has lived in the Gorbals all her life, has experienced previous heartache when another of her works, the Gorbals Boys, was vandalised in 2010.
Chief Inspector Stephen McAllister, from Gorbals police office, said: "We're look- ing into the incident and still trying to establish whether it was vandalism or theft."
Anyone with any information about the incident is asked to call 0141 532 5300 or visit Gorbals police office in Cumberland Street.