Using the data from the Program for the International Assessment of Adult Competencies (PIAAC), this Data Point summarizes the number of U.S. adults with low levels of English literacy and describes how they differ by nativity status and race/ethnicity. PIAAC is a large-scale international study of working-age adults (ages 16-65) that assesses adult skills in three domains (literacy, numeracy, and digital problem solving) and collects information on adults' education, work experience, and other background characteristics. In the United States, when the study was conducted in 2011-12 and 2013-14, respondents were first asked questions about their background, with an option to be interviewed in English or Spanish, followed by a skills assessment in English. Because the skills assessment was conducted only in English, all U.S. PIAAC literacy results are for English literacy. PIAAC defines literacy as "the ability to understand, evaluate, use and engage with written texts to participate in society, to achieve one's goals, and to develop one's knowledge and potential" (p. 61, OECD 2013). Results in this Data Point are presented as the number of adults at literacy proficiency levels that are described in terms of the types of tasks the adults are likely to complete successfully at a particular level. PIAAC reports out five literacy proficiency levels: from below level 1 to level 4/5. Adults with low levels of literacy are defined, consistent with international reports (OECD 2013), as those performing on PIAAC's literacy assessment at "level 1 or below" or those who could not participate in the survey.