For every person that succeeds in taking their own life there are at least 20 more who try, the WHO said in a report timed to coincide with World Suicide Prevention Day.
"Today, too many people of all ages needlessly take their own lives," the UN agency said. "For family and friends affected by suicide or attempted suicide, the emotional impact may last for many years."
The WHO said the global suicide rate was up 60 percent over the last 50 years with an even more marked increase in the developed world.
Suicide is now among the top three causes of death among people between 15 and 34 years old, but most suicide victims are found among the elderly, those aged 60 and above, it said.
The WHO said it was working "to ensure that suicide is no longer seen as a taboo or an acceptable result of personal or social crises, but as a health condition influenced by psycho-social, cultural and environmental risk factors."