Understanding text in a second language can be particularly challenging. The authors explored the contribution of morphological awareness in children's first and second languages to development in second-language reading comprehension. Critically, the authors examined the role of a skill that might be at the heart of these cross-linguistic connections: awareness of cross-language suffix correspondences. This is the awareness, for instance, that the French suffix -eux and the English suffix -ous have the same meaning in the two languages, despite the fact that they look and sound different. The authors tested the contributions of each of these morphological skills to French reading comprehension in a study of students with diverse first languages enrolled in a Canadian early French immersion program with instruction entirely in French. Seventy-five students were tested in grade 2 and again in grade 3. In grade 2, students completed measures of English and French morphological awareness and awareness of cross-language suffix correspondences, along with control measures of nonverbal ability, French vocabulary, and French phonological awareness. In grades 2 and 3, students completed measures of French reading comprehension. The authors found that both English and French morphological awareness were related to grade 3 reading comprehension. Neither relation was significant after the autoregressor. In contrast, awareness of cross-language suffix correspondences predicted individual differences in French reading comprehension, including after autoregressive controls. These findings show the importance of awareness of commonalities between suffixes across languages in enabling the development of French reading comprehension.