The sharp increase in the number of women in parliament in recent years represents an important step towards achieving the principles essential to democracy. While this is beneficial for representative democracy, it has tended to disrupt the established order, provoking some resistance. Such resistance can take different forms, such as sexist insults and remarks, intimidation or harassment. Directed against women in politics, such behaviour is particularly troubling. This Issues Brief aims to clearly delineate the issues at stake by analyzing the results of a first study specifically devoted to the subject of sexism, harassment and violence against women in parliament. It seeks to clarify what this phenomenon consists of, where, why and in what forms it occurs, who are the perpertrators and what is its prevalence. It also seeks to alert parliaments to the issue and encourage them to address it, in particular by defining the issues at stakes for their proper functioning, inclusiveness, representative character and determination to achieve equality between men and women.