This paper summarizes the methods for evaluating the selectivity of fishing gear, including species- and size-selection resulting from various kinds of fishing gear and sorting devices, which have been developed by the authors over the last 30 years. Firstly, we briefly outline the master curve method to estimate the trawl selection curve of target mesh size, based on the Baranov’s geometrical similarity assumption that there is a geometrical similarity in the combination of body size and mesh opening at a given retention probability. Secondly, we review the development process of the SELECT method for estimating a selection curve with an explanation of the factors affecting split parameters in the SELECT method, such as fishing effort, catchability, and sampling fraction. Thirdly, we describe the conditions for data pooling in replicated comparative fishing experiments with fishing gears of different specifications. Finally, we outline a contact probability model for evaluating contact selection and available selection of towed net with a sorting device, such as grids, square mesh windows, and dredge tooth.