Studies show that morphological and lexical awareness is a particularly important variable for reading comprehension after the primary school years. Research on L1 students' reading and writing competence has revealed correlations between reading and writing with regard to metalinguistic awareness, specifically also with regard to the subtypes: morphological and lexical awareness. Conversely, studies of L2 reading and writing relations are scarce and partial. In this paper, we study potential correlations between reading and writing regarding morphological and lexical awareness for 3rd-6th grade students with Norwegian as a second language. A reading-writing pattern emerges showing that derivational morphological features in the students' reading correlate with derivational features in the students' writing, whereas we find no significant correlations for compositional and inflectional morphology in the reading-writing relation in our study. In addition, complex expressions, also called opaque expressions, are found to be partially understood by the students when they read, but these kinds of expressions are almost absent in their writing. The study contributes to filling in the picture of how the two literacy activities--reading and writing--interact in a L2 literacy development perspective.