Older children in Scotland are less likely to drink regularly, smoke or eat unhealthy food than they were a decade ago.
A study carried out at Edinburgh University found the number of 11 to 15-year-olds who drank once a week or more has fallen by more than a third over the last decade.
They also smoked less and had a healthier diet, but many struggled to meet government guidelines on exercise.
The team of researchers questioned nearly 7000 young people for the Health Behaviours in School-Aged Children (HBSC) Scotland National Report, funded by NHS Scotland.
The proportion of 15-year-olds who smoke daily has fallen from 16% to 11% since 2002, while daily sweet consumption has reduced by a third and the amount of crisps and chips consumed has halved.
However, less than a fifth of boys (19%) and only one in nine girls achieved the recommended weekly level of exercise.
Nearly nine in ten youngsters (87%) said they were satisfied with their life, although happiness levels dipped over the ten years.
There was an increase in the number of children reporting that their family was financially well off, and a higher percentage felt they could talk to their fathers about their problems.
Professor Candace Currie, director of the Child and Adolescent Research Unit at the University of Edinburgh, said: "These recent findings are extremely encouraging with improvements in several areas relating to children's overall well-being."