This study investigated an adaptation of the Oral Reading Fluency (ORF) measure of the Dynamic Indicators of Basic Early Literacy Skills into a European context for the Norwegian language, which has a more transparent orthography than English. Second-order latent growth curve modeling was used to examine the longitudinal measurement invariance of the ORF measure, the growth in oral reading fluency within and across grades 2-5, the relative stability of the ORF measure, and the relationship between the ORF measure and high-stakes national tests of reading proficiency. Results showed that the ORF passages measured the same underlying construct, but some passages stood out regarding the invariance pattern. The oral reading fluency growth curve models demonstrated a linear growth in grades 2 and 3 and a nonlinear growth in grades 4 and 5. Initial individual differences varied more than growth rates, which for all were positive but largest in grades 3 and 4. High relative stability in the ORF measure was found across grades. The concurrent and predictive relations of the ORF measure on the Norwegian national reading tests were moderate to strong (range = 0.44-0.75). Findings indicated that the ORF is a reliable and valid measure of reading in Norwegian grades 2-5 and easy and fast to administer. The ORF measure might contribute to early identification of students at risk for reading difficulties in an orthography more transparent than English. Implications for school practice and future research are discussed.