The third ACM International Workshop on Multimedia Content Analysis in Sports (ACM MMSports'20) is part of the ACM International Conference on Multimedia 2020 (ACM Multimedia 2020). Exceptionally, due to the corona pandemic, the workshop is held virtually. The goal of this workshop is to bring together researchers and practitioners from academia and industry to address challenges and report progress in mining, analyzing, understanding and visualizing the multimedia/multimodal data in sports. The combination of sports and modern technology offers a novel and intriguing field of research with promising approaches for visual broadcast augmentation, understanding, statistical analysis and evaluation, and sensor fusion. There is a lack of research communities focusing on the fusion of multiple modalities. We are helping to close this research gap with this workshop series on multimedia content analysis in sports.