This study compared the reading and oral language skills of children who speak English as a first (L1) and second language (L2), and examined whether the strength of the relationship between word reading, oral language, and reading comprehension was invariant (equivalent) across the two groups. The participants included 183 L1 and L2 children (M = 9; 7 years, SD = 3.64 months) in England. As anticipated, there was a significant L1 advantage for oral language (i.e., vocabulary, verbal working memory, sentence repetition) and reading comprehension but not for word reading. Findings from the multigroup structural analysis indicated that the strength of relationships between oral language and reading was relatively invariant across the two groups. Oral language was the strongest predictor of reading comprehension levels in both groups. Finally, the weaker English oral language skills explained the lower performance of L2 learners on reading comprehension. Together the results underscored the importance of supporting oral language development in minority language learners.