This book constitutes the refereed proceedings of the 13th International Conference on Model and Data Engineering, MEDI 2024, held in Naples, Italy, during November 18–20, 2024. The 7 full papers and 11 short papers were carefully peer reviewed and selected from 45 submissions. They were organized in topical sections as follows: AI-Enabled Systems; Security and Privacy; Query Processing; Prediction; Conceptual Issues; and Applications.