Morphology is the study of the structure and content of morphemes, which are the smallest, meaningful grammatical units in language, and the process of word-formation (Nagy, Carlisle, & Goodwin, 2014). Morphological awareness refers to the ability to analyse these units in a non-communicative context (Kuo & Anderson, 2006). Morphological awareness has been an emerging topic of research in recent decades. In the course of time, research increasingly suggests that morphological awareness plays a role in the development of literacy skills such as word reading, reading comprehension, spelling, and vocabulary (Carlisle & Goodwin, 2014; Kuo & Anderson, 2006; Nagy et al., 2014). Further, findings indicate that morphological instruction benefit both students with and without reading difficulties (Bowers, Kirby, & Deacon, 2010a). Morphological instruction may thus have educational consequences for all students and may ultimately contribute to reducing the gaps between the average and the weaker readers, in turn, making this an interesting field for both general and special needs educators. Even though most of the research on morphological awareness has been done on English speakers, research on the development of morphological awareness has indicated a similar development of morphological awareness across languages (Kuo & Anderson, 2006). In this study data from two measurements of morphological awareness are analysed to study whether the development of morphological awareness to follows a similar course in Norwegian monolingual children. There are some challenges related to the measurement of constructs which are not directly observable, such as morphological awareness. In the testing of such constructs there is a risk of measuring other constructs that are related to either the content of the tests or the execution of the tests. To assess the influence of such confounding variables it is relevant to use covariates. In this study the influence of the covariates vocabulary, which may be a confounding variable for the content of tests, and working memory which may be related to the execution of the tests, are included on the analysis.