The importance of emotional awareness (EA) and emotion regulation (ER) for children's and adolescents' development has been suggested in numerous studies, but longitudinal trajectories of these aspects of emotional competence have rarely been examined. Therefore, the main aim of this study was to investigate developmental trends of EA and ER in early and middle adolescence over a 1-year period. Longitudinal increases of different aspects of EA (emotion differentiation, bodily unawareness, attention to others', and analyses of own emotions) and dysfunctional ER, and decreases of functional ER were expected. Furthermore, it was explored whether these trajectories as well as their initial levels were associated with gender and age. Three-wave longitudinal self-report data of N = 1,225 German adolescents (aged 10-15 years at initial assessment, 54% female) who had completed the Emotion Awareness Questionnaire and the Regulation of Emotions Questionnaire were analyzed. After establishing at least partial scalar measurement invariance for the longitudinal models, the second-order Latent Growth Curve Models (LGCMs) were computed. Regarding EA, increases of emotion differentiation and bodily unawareness, as well as adolescents' attention to others' emotions, but also a decrease of their willingness to analyze own emotions were found. For ER, results suggested stability of dysfunctional and decreases of functional strategies. Conditional LGCMs (including gender, age, and the interaction between both) indicated that the increase of emotion differentiation and the decrease in the use of selected functional ER strategies were more pronounced for younger participants. Gender differences were found only for baseline but not for developmental trends, and no significant interaction with age was found. Overall, this study illustrates the developmental trajectories of EA and ER over the course of 1 year and emphasizes that adolescents have difficulties in applying functional ER strategies with increasing age, despite improvements in EA.