This book constitutes revised selected papers from the 6th International Conference on Deep Learning Theory and Applications, DeLTA 2025, which took place in Bilbao, Spain, during June 12-13, 2025.

The 9 full papers and 13 short papers presented in this volume were carefully reviewed and selected from 42 submissions. The conference is focusing on models and algorithms; machine learning; Big Data analytics; computer vision applications; and natural language understanding.