This study examined the co-occurrence of word reading difficulty in Chinese (L1) and English as a second language (L2) and tested language and executive functioning (EF) skills as correlates. Thirty-nine poor readers in Chinese (PC), 39 poor readers in English (PE), and 26 poor readers of both languages (PB) were compared to 39 average readers who served as controls (C). The co-occurrence rate of L1-L2 difficulty was 40%. Moreover, PC, PE, and PB performed less well than C on all language and EF skills; PB performed less well than PC, PE, and C on L1 and L2 phonological awareness, L2 morphological awareness, rapid naming, and EF. Findings highlight the role of language and EF skills in L1 and L2 reading development.