International assessments such as PIRLS and PISA (Skolverket 2021; 2023) indicate a decline in reading comprehension and increasing disparities among Swedish students. These assessments also evaluate students’ ability to understand word meanings. Research highlights that a well developed vocabulary is crucial for reading comprehension (Nagy & Scott, 2000), and the Swedish National Agency for Education (2020) emphasizes that instruction should actively promote vocabulary development as a prerequisite for educational equity and, ultimately, a democratic society.This study investigates how explicit and structured instruction in morphology, with a focus on derivational affixes (derivational prefixes and derivational suffixes), can support the develop-ment of students’ morphological awareness—skills that previous research suggests are essential for interpreting the meaning of unfamiliar words, and thus important for both language and reading development (Apel & Henbest 2016; Graves, Schneider & Ringstaff 2017). The study is grounded in variation theory (Lo 2013) and was conducted as a learning study in two fifth-grade classrooms. Pre- and post-tests were designed by the researchers based on Apel’s (2014) definition of morphological awareness and selected assessment aspects intended to evaluate students’ practical morphological skills (Apel, Henbest & Petscher 2021). The tests were used to examine students’ morphological awareness before and after the intervention. The results demonstrate a clear development in students’ morphological awareness, particularly in their ability to segment and identify morphemes. The analysis also indicates an emerging understanding of how derivational prefixes and derivational suffixes influence word meaning and function. Overall, the study shows that explicit instruction in morphology focusing on derivation can enhance students’ morphological awareness, which in turn can support their ability to interpret new words and thereby improve reading comprehension (Apel & Werfel 2014).