This study examines the effects of an electronic reading environment's structure on second language (L2) reading comprehension. In particular, this study explores whether clarifying the underlying structure of an electronic text, along with the ways in which its units or nodes are organized and interrelated results in better comprehension as well as whether L2 reading proficiency affects the comprehension of electronic text. In this study, 40 English as a second language (ESL) learners, grouped into proficient and less-proficient groups based on their scores on the Test of English as a Foreign Language's (TOEFL's) Reading section, were asked to read two electronic texts using computerized programs classified as either "well structured" or "less structured." To assess the efficacy of each type of reading environment, two tests--a multiple-choice test and a mapping of main ideas and details (MOMID) test--were developed and administered to the participants after they read each text. The results of these tests were analyzed using a paired-samples "t"-test and a two-way (proficiency level by computerized reading program) mixed-model analysis of variance (ANOVA). The findings revealed that well-structured electronic texts can aid ESL readers in developing a more coherent mental representation of the electronic texts' content, thereby increasing their reading comprehension. Furthermore, well-structured electronic texts are more helpful for less-proficient readers than for more-proficient readers. These findings have significant pedagogical and technological implications for L2 reading instructors and instructional designers.