This book constitutes the thoroughly refereed post-conference proceedings of the Third APWeb-WAIM 2019 Workshops, held jointly with the Third International Joint Conference APWeb-WAIM 2019 in Macau, China, in August 2019. The 8 full papers presented together with 1 invited talk were carefully reviewed and selected from 18 submissions. The papers originating from two workshops, KGMA and DSEA, present cutting-edge ideas, results, experiences, techniques, and tools from all aspects of the management, analysis, and application of knowledge graphs in different domains, as well as theoretical foundations, algorithms, systems, models and applications for big data management and mining.