Purpose: The transition to school and the first years of elementary school education are very sensitive phases for reading development. Reading researchers have established key precursors and developmental steps in these phases. However, how these components interact and affect growth is not well understood yet. The current study from Germany replicates established findings and explores how curvilinear effects can add information to our understanding of reading development. Method: 525 German-speaking children were followed during a 5-year period from kindergarten to fourth Grade. Phonological awareness (PA), letter knowledge (LK), rapid naming (RAN) and language skills (LS) were assessed in kindergarten, decoding and reading comprehension in elementary school. Analysis was based on latent growth models with curvilinear (quadratic) effects. Results: The results indicate that PA and LK are of importance for early reading, RAN was additionally revealed to be of importance for further growth in decoding. Language skills and decoding, together with their interaction, explain variation in reading comprehension skills. A curvilinear effect was found for decoding on reading comprehension growth only. Conclusion: Our study shows which precursors predict growth in reading development in a transparent orthography and expands our understanding of how language and decoding affect the development of reading comprehension.