Micro-facial expressions (MEs) are involuntary movements of the face that occur spontaneously when a person experiences an emotion but attempts to suppress or repress the facial expression, most likely in a high-stakes environment. Computational analysis and automation of tasks on micro expressions is an emerging area in face research, with a strong interest appearing as recent as 2014. Only recently, the availability of a few spontaneously induced facial micro-expression datasets has provided the impetus to advance further from the computational aspect. CAS(ME)2 and SAMM are two facial macro- and micro- expression databases which contain long video sequences. While much research has been done on short videos, there has been not many attempts to spot micro-expressions on long videos. This workshop is organized with the aim of promoting interactions between researchers and scholars from within this niche area of research, and also those from broader, general areas of computer vision and psychology research. This workshop has two main agenda: 1) To organize the third Grand Challenge for facial micro-expression research, involving spotting macro- and micro-expression on long videos in CAS(ME)2; and 2) To solicit original works that address a variety of modern challenges of ME research such as ME recognition by self-supervised learning.