Reading comprehension is a multi-dimensional process that includes the reader, the text, and factors associated with the activity of reading. Most research and theories of comprehension are based primarily on research conducted with monolingual English speakers (L1). The present study was designed to investigate the cognitive and linguistic factors that have an influence on reading comprehension in English-as-a-Second-Language (ESL) speakers. The cognitive aspects of reading comprehension among L1 speakers and ESL speakers in the seventh grade were investigated. The performance of both groups was compared and the role of some relevant processes, including word reading, word reading fluency, phonological awareness, working memory, and morphological and syntactic awareness were assessed. Within this sample, three groups were examined: (1) children with poor comprehension (PC) in the absence of word reading difficulties (2) children with poor word reading and poor comprehension (poor readers, PR) (3) and children with both good word reading and comprehension abilities (good comprehenders, GC). The results demonstrated that a variety of cognitive processes, such as working memory and phonological, syntactic, and morphological awareness are important for reading comprehension and compromised in poor comprehenders. The GC group performed better than the PC group on all of the cognitive measures, indicating that comprehension depends on a variety of phonological, memory and linguistic processes and that adequate word recognition skill are important for reading comprehension. The prevalence of the ESL and L1 students was similar across the three reading groups. The ESL and L1 students demonstrated similar performance, indicating that the skills underlying reading comprehension are similar in the ESL and L1 students. This study demonstrated that ESL students are capable of developing word reading and reading comprehension skills that are as strong as those of their L1 peers.