This book constitutes the revised selected papers from the 15th International Conference on Cloud Computing and Services Science, CLOSER 2025, held in Porto, Portugal, during April 1–3, 2025.

The 5 full papers and 1 short paper included in this volume were carefully reviewed and selected from 41 submissions. They focus on current research trends in Cloud Computing and Services Science, including Cloud Management and Operations, Cloud Continuum, Cloud Optimization and Automation, Cloud Application Architectures, Cloud Solution Design Patterns, Cloud Workflow Management Systems, Container Composition and Orchestration, Microservices, Microservices: Automation, Deployment and Management, Resource Allocation Elasticity, Service State and Resilience and Monitoring of Services, Quality of Service, Service Level Agreements.