Abstract: Older adults are increasingly accessing the web for numerous reasons: searching for health and travel information, socializing with friends and family, or simply for entertainment.Accommodating and designing for the range of skills, experience, and physical and mental abilities of this user group can be a challenge.Although the causes may differ, commonalities are often found among older adults and people with disabilities in terms of perceptual, motor, and cognitive issues with web usage.Web Accessibility for Older Users was the theme of the W4A (Web-4-All) conference in 2009 and, from a list of the many high-quality papers presented at the conference, the most relevant, innovative work was selected for extension in this special issue.This collection of articles addresses the growing need to better understand the current motivations, uses, and barriers for older adults in accessing the web, the subsequent design and improvement to accessibility guidelines to better include older adults, and the factors that have led to the current usage levels and the extent to which those factors will continue to effect technology usage for the next generation of older adults.Understanding barriers that may hinder this unique and diverse population in accessing the web is an important first step.Three articles in this special issue further current knowledge of Internet use, common problems encountered, and factors that prevent access altogether for older adults.