Education is in general the basis for development in any country in the world. In the education al field, several international assessments (Pisa, 2006) reflect the great gap that yet subsists among developing countries, in which the case of Peru is not an exception. There have been many national and international academic achievement evaluations that examine the skills and knowledge of students not only in Peru but also in other Latin American countries in different academic domains. One of these examples is the Regional Comparative and Explanatory Study (LLECE), in which Peru participated, in order to evaluate and compare the performance achieved by Latin American students of 3rd and 6th grade in core areas like Language, Mathematics, and Natural Sciences. Peru ranks, together with other Latin countries, with scores below the average (Regional Office for Education of UNESCO, 2008). The low ranking of the Peruvian educational system carries heavy implications and consequences, especially to the intellectual and social development of learning disabled Peruvian children. Understanding the relation between academic performance and child development is of paramount importance. The present study examines how spelling, reading and arithmetic performances are associated to various child variables (gender, intelligence, and age), and distal variables such as Socio-Economic Status (SES) or type of school. The subjects in the study were 1.129 elementary school children who were in the 6th grade (11 - 12 years old) in Metropolitan Lima, Perú. Children complet - ed four different tests: In the reading area, the subtest of Procesos Lectores (PROLEC-SE; Cuetos & Ramos, 1999), Reading of Word and Pseudo-word; in the Arithmetic domain, the Number Facility from the Kit of Factor Referenced Cognitive Tests of Ekstrom, French, and Harman (1979) and in the spelling domain, the Spelling Achievement Test from Dioses (2001) was used. The Intelligence Quotient (IQ) was measured using Raven's Progressive Matrices Test (Raven, J., Raven, J.C., & Court, 2004, updated edition). Some preliminary analyses were conducted beforehand in order to overview and examine the structure of the data. Following this, and because of the hierarchical structure of the data (students within classes within schools) multilevel analyses were conducted. Results showed, first and foremost, a great impact of (a) type of school, private schools performed better than in the public sector; (b) intelligence, another essential variable (the higher the IQ the better the academic achievement), and partially of (c) gender, girls showed prevalence over boys in spelling. Likewise, we did not encounter any significant results of socioeconomic status in the multilevel analysis. Based on these results, some practical and pedagogical implications were discussed, such as the fundamental effort to bring the lower achievement group into average levels of learning with remedial work, otherwise these students will lack the requisite skills needed to fulfill their secondary school academic expectations. Notwithstanding, we have to point out some limitations such as the lack of data from rural zones that could prevent us from comparisons between rural and urban zones. Future work is necessary in order to investigate academic performance associated with other variables that might influence the child's development, such as parenting behavior or psychosocial factors. [ABSTRACT FROM AUTHOR]