Alun Griffiths, head of Cefn Saeson comprehensive, in Neath, has written to parents to counter claims that vicious bullying was taking place on the site.
In the school newsletter, he wrote: "Of course, we were deeply saddened by the death. But the school did everything to help Laura Rhodes and her family, and provided access to every appropriate support service."
Laura and her best friend Rebecca Ling, from Birmingham, took an overdose of painkillers in a bed-and-breakfast-hotel in Bath last month after running away from home together.
Rebecca survived the suicide bid and was questioned by investigating officers. But this week police said they would not be pressing charges.
A spokesperson for South Wales police said: "Under advice from the Crown Prosecution Service, we will not be prosecuting Rebecca Ling for any offences. It's a matter now for the coroner to consider."
The case will come before the coroner in the new year. Laura's parents, Yvonne and Michael Rhodes, have said that she was driven to her death by bullies at Cefn Saeson. In a letter about her experiences, Laura wrote: "I got fatter and fatter and sadder and sadder. Everyone got meaner and meaner."
But Mr Griffiths believes the school has been unfairly maligned. He told The TES: "Pupils here don't recognise the way their school has been portrayed. It has been vicious, wicked and evil. But our conscience is clear. I'm not saying bullying doesn't take place. We reflect society, and bullying is everywhere. The problem is people who can't distinguish between kids squabbling and extensive bullying."
Cefn Saeson's student council has issued a statement defending the comprehensive. The pupils said: "An image has been created of our school in the past few weeks. It is one we do not recognise. There is a brilliant relationship between teachers and pupils. They are forever willing to give up their free time to help us."