The aim of this study is to explore the relation of morphological awareness to vocabulary, word reading, and reading comprehension for middle school students in Korea. A total of 121 students (73 boys and 48 girls) in Grade 7 from two middle schools in a metropolitan city in South Korea participated in the study. The students were assessed on the following skills in Korean: morphological awareness in three dimensions (inflectional, derivational, and compound morphological awareness), vocabulary, word reading, and reading comprehension. Using structural equation modeling, we found that students' morphological awareness predicted vocabulary, word reading, and reading comprehension directly. In addition, morphological awareness was also indirectly related to reading comprehension mediated by word reading. Interestingly, once morphological awareness was accounted for, vocabulary did not make an independent contribution to reading comprehension. Our findings illustrate the direct and indirect relations of morphological awareness to vocabulary, word reading, and reading comprehension for Korean adolescents.