This book constitutes the proceedings of the 12th International Conference on Big Data Analytics in Astronomy, Science, and Engineering, BDA 2024, which took place in Aizu, Japan during November 26-28, 2024. The 16 full papers included in this book were carefully reviewed and selected from 90 submissions; the proceedings also include 6 invited papers. The contributions were organized in topical sections as follows: Big Data: analysis and management; data science; big data applications; and information security.