Inspectors say too many pupils suffer from bullying during their school lives.
A report published today by Estyn also says schools have a responsibility to tackle bullying in all forms under the Education Act 2002, but the ways in which schools deal with bullying varies widely.
'Action on bullying', found that even schools with good strategies to address the problem don't have a common understanding of how important it is to focus on groups of pupils with a higher-than-average risk of being bullied.
They include gay, lesbian and transgender pupils, those with a disability and pupils from a minority ethnic background.
More top news
Wales has been labelled a blackspot for motor crimes after research revealed 172,000 motoring offences were recorded between 2015 and 2016.
Arriva Trains Wales says twelve trains were damaged by hitting fallen trees and services will be affected this morning.
Paul Clement wants to make sure Swansea's battle for Premier League survival does not see them "suffer" at the end of the season.