The book "Machine Learning and Data Mining for Sports Analytics" offers a comprehensive collection of research findings that emerged from the 8th International Workshop on this topic. The conference took place as a virtual event in September 2021 and attracted numerous contributions addressing various aspects of sports analytics. This volume includes 12 full papers and 4 short papers, selected from a total of 29 submitted works. The topics covered range from tactical analyses and outcome predictions to data acquisition, performance optimization, and player evaluation. The careful review and selection of contributions ensure a high level of scientific quality and relevance for professionals and researchers in the field of sports analytics.