In the past, unilateral hearing loss (UHL) in children was thought to have little consequence because speech and language presumably developed appropriately with one normal-hearing ear. Some studies from the 1980s and 1990s have suggested that a significantly increased proportion of children with UHL may have educational and/or behavioral problems, compared with their normal-hearing peers. Limited data exist about the effect of UHL on acquisition of speech and language skills. To review the current literature about the impact UHL has on the development of speech and language and educational achievement. MEDLINE search between 1966 and June 1, 2003, using the medical subject heading "hearing loss," combined with the textword "unilateral." Studies were limited to those written in English, reporting speech-language and/or educational results in children. Articles were read with attention to study design, population, recruitment of subjects, and outcomes measured. Problems in school included a 22% to 35% rate of repeating at least one grade, and 12% to 41% receiving additional educational assistance. Speech and language delays have been reported in some but not all studies. School-age children with UHL appear to have increased rates of grade failures, need for additional educational assistance, and perceived behavioral issues in the classroom. Speech and language delays may occur in some children with UHL, but it is unclear if children "catch up" as they grow older. Research into this area is necessary to clarify these issues and to determine whether interventions may prevent potential problems.