The group said that ministers had failed to deal with the issue of the bullying of disabled children, favouring instead to prioritise racism and homophobia in schools.
"We have not seen clear leadership in combating disablist bullying," the Mirror quoted Dame Jo Williams, Mencap's chief executive, as saying.
Mencap believes that bullying the disabled is destroying children's lives, leading to social exclusion in childhood and adulthood, and it said that the figures revealed by their report, 'Don't stick it Stop it! Bullying Wrecks Lives' reveals the extent of the problem.
The leading learning disability charity quizzed 500 pupils - aged eight to 19 - with a learning disability.
One boy, 17, said teachers told him, "I should get used to it as I would be bullied all my life".
The Department for Children, Schools and Families said it was working on guidance to help teachers respond better.