Somebody dies by taking their own life every 40 seconds, according to a significant report by the World Health Organization (WHO).
It said suicide was a "major public health problem" that was too often shrouded in taboo.
The WHO wants to reduce the rate of suicide by 10% by 2020, but warned just that 28 countries have a national suicide prevention strategy.
Campaigners said there needed to be more education in schools.
The WHO analysed 10 years of research and data on suicide from around the world.
- Around 800,000 people kill themselves every year
- It was the second leading cause of death in young people, aged 15 to 29
- Those over 70 were the most likely to take their own lives
- Three-quarters of these deaths were in low and middle income countries
- In richer countries, three times as many men as women die by suicide
- It said limiting access to firearms and toxic chemicals was shown to reduce rates of suicide.
And that introducing a national strategy for reducing suicides was effective, yet had been developed in only a minority of countries.
Dr Margaret Chan, the director general of the World Health Organization, said: "This report is a call for action to address a large public health problem, which has been shrouded in taboo for far too long." Social stigma attached to mental health disorders is known to stop people seeking help and can ultimately lead to suicide.
The WHO also attacked the reporting of suicide in the media, such as the details revealed about the death of Hollywood actor Robin Williams. There was also a call for countries to provide more support for people who had previously made a suicide attempt as they were the most at-risk group.
Dr Alexandra Fleischmann, a scientist in the department of mental health and substance abuse at WHO, said: "No matter where a country currently stands in suicide prevention, effective measures can be taken, even just starting at local level and on a small-scale."
Jonny Benjamin, a suicide campaigner in the UK, told the BBC: "I think there needs to be much more public awareness around suicide and how to approach people that may be experiencing suicidal thoughts and feelings, too few of us know how to react when they see someone who may be at risk of taking their life or experiencing those thoughts and feelings.
"I think there needs to be much more public awareness, much more education in schools as well because, as statistics today have shown young people are especially at risk of taking their own lives."