This volume constitutes the proceedings of the 28th International Conference on Collaboration Technologies and Social Computing, CollabTech 2022, held in Santiago, Chile during November 8-11, 2022.  The 18 full and 4 work-in-process papers presented in this volume were selected from 37 submissions and underwent careful double-blind peer review. The papers focus on innovative technical, human and organizational approaches to expand collaboration support including computer science, management science, design science, cognitive and social science.