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.