While it has been shown that socioeconomic status (SES) is important for children's literacy development in their first language (L1), less is known about its association with reading in a second language (L2). The present study examined the different effects of SES on the acquisition of reading in Chinese as L1 and English as L2 from ages 7 to 11, among 291 Chinese children. The results showed that the contribution of SES to Chinese word reading was not significant. In contrast, SES significantly predicted English word reading. Mediation analyses revealed that SES had direct and indirect effects on English word reading, through phonological awareness and letter name knowledge, but only an indirect effect on Chinese word reading through phonological awareness and vocabulary knowledge. These findings highlight the importance of SES for reading acquisition in L2, and the influence of language-specific characteristics on the cognitive/linguistic skills required to master reading in a specific language.