This book constitutes the refereed proceedings of the 17th International Conference on Social Computing and Social Media, SCSM 2025, held as part of the 27th HCI International Conference, HCII 2025, which took place in Gothenburg, Sweden, during June 22-27, 2025. A total of 1430 papers and 355 posters included in the HCII 2025 proceedings was carefully reviewed and selected from 7972 submissions. The SCSM 2025 proceedings were organized in the following topical sections- Designing and Developing Social Interactions, Social Media in Learning and Education, Supporting Communication and Psychological Well-Being, User Behavior and Experience in Social Media, and, AI and Social Network Analysis.