This book constitutes the refereed proceedings of the 8th International Conference on Information Management and Big Data, SIMBig 2021, held as a virtual event in December 2021.  The 25 revised full papers and 2 revised short papers presented were carefully reviewed and selected from 67 submissions. The papers are organized in topical sections on data mining and applications; deep learning and applications; data-driven software engineering; health, NLP, and social media; image processing, machine learning, and semantic web.