This book constitutes the proceedings of the 20th International Conference on Soft Computing Models in Industrial and Environmental Applications, SOCO 2025, held in Salamanca, Spain, during October 16–17, 2025.The 60 full papers included in this volume were carefully reviewed and selected from 133 submissions. The papers cover the following topical sections: Optimization, Metaheuristics and Applied Math; Deep Learning for Environmental, Energy and Bio-Vision Applications; Anomaly Detection and Predictive Maintenance. The papers also include the following special sessions: Time Series Forecasting in Industrial and Environmental Applications; Efficiency and Explainability in Machine Learning and Soft Computing; Intelligent Techniques Applied to Modelling and Control in Engineering focused on marine energy systems and robotics; Quantum Computing; EUropean Transnational Educational; and Machine Learning and Computer Vision in Industry 4.0.