The singer-songwriter explained that adults that read gossip columns or watch reality shows are not allowed to tell their children not to bully others.
"We watch the grand finale of The X Factor, and we get all these rejected contestants coming on to sing - possibly people with a disability, certainly the elderly - and we all just sit and laugh at them," she told The Observer.
"Then we buy gossip magazines, slagging off celebrities for walking down the street looking human, saying, 'Urgh! Look how disgusting and gross they are! They're fat and they're ugly, or they're too thin, look at their wrinkles and their crow's feet'.
"None of the adults who buy into that can turn around to kids and say, 'Don't bully each other'."
Nash launched her 'Rock 'n' Roll For Girls After School Club' last year, where she visits schools to help young girls who were interested in a music career.
During the scheme, Nash explained that she met several pupils who were the victim of bullies.
"I've been spending a year and a half meeting teenage girls who just hate themselves. They're really insecure about the way they look, and at the age of 14, dismiss the idea of becoming a musician because of the worry about how the media would treat them. It was such a wake-up call to me."
Kate Nash unveiled her brand new style and sound last month with the single 'Under-Estimate the Girl'. She later said that it is "important to push boundaries" as an artist.
Watch the video for 'Under-Estimate the Girl' below: