Librarians and libraries have long been committed to providing equitable access to information. In the past decade and a half, the growth of the Internet and the rapid increase in the number of online library resources and tools have added a new dimension to this core duty of the profession: ensuring accessibility of online resources to users with disabilities. The first step in this undertaking is gaining an understanding of the Web standards that detail the ways in which online resources can be made accessible to those who use screen readers and other assistive technology. This article briefly reviews the history of basic accessibility issues and the two major sets of Web standards and their makers: (1) the United States Federal Government's Section 508; and (2) the World Wide Web Consortium's Web Content Accessibility Guidelines (WCAG). (Contains 3 figures.)