The dictionary of accounting terms plays an important role for students as an independent learning medium because it can make it easier for students to find vocabulary so they don't need to use a general dictionary. To increase the effectiveness of using a dictionary of accounting terms, an accounting term dictionary application that is integrated with mobile devices or mobile-based applications is needed so that it is easier for users to find the meaning of a term in the accounting field. This research focuses on developing a mobile-based dictionary of accounting terms that are used as a self-learning kit (SLK) in the process of teaching writing and analyzing its implementation. This SLK was built according to ADDIE Model's adaptation. The application was built using the Waterfall method, Dart programming language, and Flutter framework. The implementation phase was carried out in a preexperimental design so that quantitative data was obtained. Quantitative data were obtained from the statistical analysis of pre-test and post-test essays written by twenty-seven students before and after a selflearning kit (dictionary application) was implemented in learning. SPSS Statistics 25 program was used to analyze the results of pre-test and post-test evaluations in order to investigate the impact of using digital dictionaries on improving student performance. Meanwhile, qualitative data was obtained from an online questionnaire in the form of a google form consisting of scale-type questions and paragraph-type questions. The responses gathered from the questionnaire were examined to investigate student perceptions of the use of a mobile-based accounting term dictionary in learning writing competence. The analysis of both quantitative and qualitative data shows that students gained enriched experience in learning writing, had improvement in their writing competence. Students also gave positive responses in the aspects of the application's compatibility, feature, content, and overall usability.