In order to develop a more uniform approach to determining the population of limited-English-proficient (LEP) individuals in the United States, and for purposes of educational decisions and resource allocation, the definition of this particular population is discussed in this theme issue. First, approaches currently used to estimate the size of the population and the variety of definitions are examined. Federal and state definitions are given, to exemplify the disagreement states and districts have over how to identify the LEP population accurately. Recommendations are made for a standardized definition, and the advantages and disadvantages of doing so are outlined. An appendix lists recent estimates of the LEP population and an explanation of each. Contains nine references. (MSE)