This book constitutes the proceedings of the 13th International Conference on Big Data and Artificial Intelligence, BDA 2025, held in Bangalore, India, during July 17&20, 2025. The 15 full papers and 13 short papers included in this book were carefully reviewed and selected from 104 submissions. They were organized in topical sections as follows: Language Understanding and Interactive AI; Learning Paradigms and Optimisations; ML Frameworks and System-Level Intelligence; Deep Learning Architectures and Model Design; Deep Learning Architecture and Adaptations; Domain-Specific AI Models; and Fine-Tuning and Generative Modeling Techniques.