This two-volume set LNCS 13188 - 13189 constitutes the refereed proceedings of the 6th Asian Conference on Pattern Recognition, ACPR 2021, held in Jeju Island, South Korea, in November 2021. The 85 full papers presented were carefully reviewed and selected from 154 submissions. The papers are organized in topics on: classification, action and video and motion, object detection and anomaly, segmentation, grouping and shape, face and body and biometrics, adversarial learning and networks, computational photography, learning theory and optimization, applications, medical and robotics, computer vision and robot vision.