Summary writing is an important tactic for learning from text and the summaries provide information on students' comprehension and learning processes. We investigated the nature of the summaries produced by bilingual adolescents, and whether their summaries were related to their reading abilities in their first and second languages. In each language, we examined the performance of students identified as typically developing, poor decoders, or poor comprehenders. Participants were 246 grade 8 students enrolled in English immersion programs in China. Measures included English word reading and reading comprehension, Chinese word reading and reading comprehension, and nonverbal ability. Students' text-absent summaries of an English 254-word expository passage were analyzed for the number of themes, main ideas, important details, and unimportant details. Using latent profile analysis, participants were identified as typical readers (TR, n = 123), poor decoders (PD, n = 74), or poor comprehenders (PC, n = 49) in English, and TR (n = 129), PD (n = 74), or PC (n = 43) in Chinese, based on word reading and reading comprehension in both English and Chinese. MANCOVA results showed that after controlling for nonverbal ability, in the English-defined groups, the TR group outperformed PD and PC on themes, main ideas, and important details; in the Chinese-defined groups, the TR group outperformed PD and PC on themes, TR performed better than PC on main ideas and important details, and PD outperformed PC on main ideas. Discussion focuses on the difficulties faced by bilingual students with reading difficulties and on the potential of summary writing instruction to improve their comprehension and learning processes.