Modern software systems are distributed, concurrent, mobile, and often involve the composition of heterogeneous components and of stand-alone services. Theoretical models, languages and tools for coordinating, composing and adapting services are hence required. They can indeed simplify the development of complex distributed service-based systems, enable functional correctness proofs and improve reusability and maintainability of such systems. This Special Issue (SI) is dedicated to Foundations of Coordination Languages and Self-adaptive Systems. This SI is a follow-up of the FOCLASA workshop that we organized at the 15th International Conference on Software Engineering and Formal Methods (SEFM 2017), held in Trento, Italy on September 4-8, 2017. The workshop received 16 full paper submissions. After a careful reviewing process, the international Program Committee decided to select seven papers for presentation during the workshop and inclusion in the FOCLASA'17 proceedings. From these papers, the six best papers were selected and invited for an extended version to this special issue. All the submissions went through a rigorous peer review process; four papers were finally accepted and are included in this special issue. These papers provide key insights on different aspects of coordination languages and self-adaptive systems.