This study explored components of language comprehension (vocabulary, grammar, and higher-level language) skills for poor comprehenders in French immersion. We identified three groups of bilingual comprehenders (poor, average, and good) based on English reading performance and compared their language comprehension skills in English L1 and French L2. We also identified and compared English skills for three groups of monolingual comprehenders from English-stream programmes. Among both bilingual and monolingual learners, poor comprehenders performed significantly lower than good comprehenders on English vocabulary, morphological awareness, and inference. Bilingual poor comprehenders also differed from average comprehenders on English morphological awareness and inference. Similar results were found in French for the bilingual learners. Lower scores on French vocabulary and morphological awareness distinguished between bilingual poor and good comprehenders. Additionally, weaknesses in French semantics and inference distinguished between bilingual poor and good comprehenders and bilingual poor and average comprehenders. These results suggest that poor comprehenders share remarkably similar language characteristics in L1 and L2.