The paper explores some of the developments in the philosophy and epistemology of language testing with particular reference to the notion of ‘responsibility’. This term is used to include the ethical practices of the individual language testing practitioner; the professional standards to which language testing as professional practice should be held; and the accountability to society and by society that should drive all those involved in the industry of creating, administering, consuming, preparing people for, and critiquing tests. The paper argues that as the millennium changes, language testing is at a point of change too. Contending with complexities on multiple levels, the future is still unclear, but we can see that it will take us in some directions quite different from the past.