This book constitutes the refereed proceedings of the 9th International Conference on Virtual, Augmented and Mixed Reality, VAMR 2017, held as part of HCI International 2017 in Vancouver, BC, Canada. HCII 2017 received a total of 4340 submissions, of which 1228 papers were accepted for publication after a careful reviewing process. The 45 papers presented in this volume were organized in topical sections named: developing virtual and augmented environments; interaction techniques in VAMR; VAMR in education and training; virtual worlds and games; user experience in VAMR; and health issues in VR.