ABSTRACT European identity formation is a component of political identity and linked to the support of European institutions and values. To understand how it develops, we examined three processes of identity formation (commitment, in-depth exploration, and reconsideration of commitment) on a short- and mid-term time scale, and their interrelations. A total of 371 German adolescents (M age = 14.24, SD age = 0.55, 60.37% females) participated in a longitudinal study and in a ten-day daily diary study. We conducted latent growth curve analysis (LGCM) and assessed rank-order stability and profile similarity for both time scales. Next, conditional LGCMs were run to examine associations of both time scales. We found a significant increase of all identity processes from the beginning to the middle of the school year and a significant decrease from the middle to the end of the school year. Across 10 days, growth curves varied according to the identity process. Stabilities were high for both time scales. Commitment at the beginning of the school year was negatively associated with fluctuations in commitment. Our results highlight the importance of examining different time scales and focusing on specific domains for understanding identity development in adolescence. They further indicate that short-term processes are associated with long-term development.