The term 'horizontal hostility' was coined by Florynce Kennedy in 1970. It refers to forms of power-as-domination between and among women which spring from a position of weakness not strength. It is a type of bullying of those perceived as powerful, driven by resentment and contempt. It involves complicity with the oppressive social order of male supremacy and compliance with the belief in female weakness. The paper discusses name-calling, the inadequacy of feelings as a justification for action, how to recognise horizontal hostility, and how to avoid engaging in it.