The widespread use of mobile applications in education has led to the need for reliable and valid measurement tools to assess their impact on language learning, particularly among young learners. This study investigated the developmental process and psychometric properties of the Children's Educational Mobile Application Usage for Foreign Languages Scale. The item pool was created by examining the studies obtained from the literature review. To evaluate the appearance and content validity of the scale, the expert assessment of the scale, which the researcher developed, was applied to 19 experts. Consequently, the experts' opinions were considered to update the Children's Educational Mobile Application Usage for Foreign Languages Scale. Pilot studies were conducted with 37 students in the 4th grade. Data were collected from 309 4th-grade students to conduct reliability and validity studies. Confirmatory Factor Analysis was used to determine the scale's construct validity. The Chi-square/degrees of freedom ratio is 2.54, and the Comparative Fit Index value is calculated as .954. The Confirmatory Factor Analysis confirmed the theoretical structure consisting of 16 items with three factors, and the compliance indices showed perfect compliance. Cronbach Alpha (α) coefficient was used to determine the scale's reliability. The Cronbach Alpha value is calculated as 0.945. As a result, the Children's Educational Mobile Application Usage for Foreign Languages Scale was valid and reliable. The study highlights the novelty of the scale, being one of the first psychometric scales in the literature explicitly targeting children's educational mobile application usage for foreign language learning. It can aid institutions in developing or updating mobile applications and investigating the relationship between children's educational mobile application use and other variables. While this study presents a valuable contribution to the field, it also acknowledges limitations, such as the sample size and reliance on personal statements for data collection. Nonetheless, Children’s Educational Mobile Application Usage for Foreign Languages opens new avenues for research and has the potential to enhance language education by harnessing innovative technology-driven approaches.