Perinatally HIV-infected youths are reaching adolescence in large numbers. Little is known about their cognitive functioning. This study aims to describe and compare the receptive language ability, word recognition skills, and school functioning of older school-aged children and adolescents perinatally HIV infected (HIV-positive) and perinatally HIV-exposed but uninfected (seroreverters; HIV-negative). Participants included 340 youths (206 HIV-positive, 134 HIV-negative), 9-16 years old, and their caregivers. Youths completed the Peabody Picture Vocabulary Test, Third Edition (PPVT-III) and the Reading Subtest of the Wide Range Achievement Test, Third Edition (WRAT-3). Caregivers were interviewed regarding demographic characteristics and school placement of youths. Medical information was abstracted from medical charts. Both groups of youths scored poorly on the PPVT-III and WRAT-3 with about one third of youths scoring in less than the 10th percentile. The HIV-positive youths scored lower than the seroreverters (M = 83.8 versus 87.6, t = 2.21, p = 0.028) on the PPVT-III and on the WRAT-3 (M = 88.2 versus 93.8, t = 2.69, p = 0.008). Among the HIV-positive youths, neither CD4+ cell count, HIV RNA viral load or Centers for Disease Control and Prevention (CDC) classification were significantly associated with either PPVT-III or WRAT-3 scores. However, youths who were taking antiretroviral medication had lower WRAT-3 scores than youths not taking medication (M = 95.03 versus 86.89, t = 2.38, p = 0.018). HIV status remained significantly associated with PPVT-III and WRAT-3 standard scores after adjusting for demographic variables. Many youths had been retained in school and attended special education classes. Findings highlight poor language ability among youths infected with and affected by HIV, and the importance of educational interventions that address this emerging need.