The UK came bottom of the league table for child well-being across 21 industrialised countries.
The USA came second bottom.
The Unicef report examined 'poverty', 'peer and family relationships', 'health' and a number of other aspects of physical and emotional well-being.
The research found British children regard themselves as less happy, drink more alcohol, take more drugs, and had more underage sex than children elsewhere.
British children were also more prone to failure at school, to experience violence, bullying and suffer a greater number of unhappy relationships with both their families and peers.
In education, the UK came behind former eastern bloc countries, including Poland and the Czech Republic.
Small independent countries topped the league: The Netherlands, followed by Sweden, Denmark and Finland.
The Unicef study found that Britain had the lowest proportion of children who found their friends kind and helpful - 40%, compared to 80% in Switzerland.
According to the report, UK child poverty has doubled since 1979.
UK is accused of failing children
British children: poorer, at greater risk and more insecure
The children left in the shadows