This study utilized research and development design in the development and validation of a Self-Learning Digital Module (SLDM) in Mathematics 9, a Junior High School subject in the Philippine K-12 Curriculum. Mathematics 9 consists of Algebra in the first and second quarters, Geometry in the third quarter, and Trigonometry in the fourth quarter. Ten (10) subject matter experts in Mathematics 9 identified the essential and nonessential learning competencies using the Evaluation Instrument for Topics to be Included in the DE/ODel Module. Using the Lawshe's content validity ratio (CVR), 44 out of 48 learning competencies in the subject were considered essential. The developed SLDM consisted of twenty-eight (28) modules which were developed in Google Classroom, a learning management system. The Evaluation Rating Sheet for DE and ODeL Modules was used by the seven experts who evaluated the content, format, technical/ technological, and pedagogical aspects of the developed module. The SLDM underwent revisions based on the suggestions and recommendations of the experts. In the final validation, all the indicators in each factor were marked yes. Furthermore, the nominal data were tallied in the initial and final stages of the validation and their frequencies served as the statistical tool in the study. Based on the results, the developed Self-Learning Digital Module in Mathematics 9 is valid and acceptable in terms of content, format, technical/technological, and pedagogy. Therefore, the developed digital module can be used as a standard learning material in teaching Mathematics 9. Keywords: Digital Module, Mathematics 9, Google Classroom, Learning Management System, ODeL