Background: Children with dyslexia often show second-language reading and writing difficulties, but the cognitive mechanisms connected to this impairment need to be clarified. Aims: The present study examined the neuropsychological mechanisms underlying learning English as a foreign language in 4th- to the 8th-grade Italian students showing reading difficulties (RD) or typical development (TD). For this purpose, screening involving 901 students was carried out to select children with RD. Sample: Ninety students with RD were compared with 90 typically developing (TD) children matched for non-verbal IQ, grade, and gender. Methods: The two groups were compared on different measures to understand the relationships between reading skills in their mother tongue and in English as a second-language (L2). Subsequently, their phonological and memory skills were investigated to understand the potential role of these variables in learning L2 English. Results: Students with RD obtained worse results than TD students for phonological awareness and working memory, which are both crucial to L2 learning. Conclusions: The results suggest that memory mainly influences accuracy in English writing and, together with phonological skills, plays an important role in reading accuracy. Socio-economic status also plays an important role in L2 learning.