This chapter discusses gender. Mainstream political theorists have often ignored the issue of gender difference, and so feminists have had to argue for its significance and importance. There are many varieties of feminism, just as there are many varieties of liberalism or egalitarianism. However, it is possible to identify three theses that all feminists support, in one form or another. These theses are the entrenchment of gender; the existence of patriarchy; and the need for change. A key theme of feminist theory has been the idea that it is vital to distinguish the terms ‘sex’ and ‘gender’. According to the distinction, ‘sex’ refers to biological differences and ‘gender’ refers to social differences. Feminists use philosophical and political methods that are common to other theories or campaigns, but there are some distinctively feminist methods, such as the Woman Question and consciousness raising.