This seven-volume set constitutes the refereed proceedings of the Human Computer Interaction thematic area of the 27th International Conference on Human-Computer Interaction, HCII 2025, held in Gothenburg, Sweden, during June 22&27, 2025. The HCI Thematic Area constitutes a forum for scientific research and addressing challenging and innovative topics in Human-Computer Interaction theory, methodology and practice, including, for example, novel theoretical approaches to interaction, novel user interface concepts and technologies, novel interaction devices, UI development methods, environments and tools, multimodal user interfaces, emotions in HCI, aesthetic issues, HCI and children, evaluation methods and tools, and many others.