Using the Gouy-Chapman theory of electrical double layer, the nature of repulsive force between two nonparallel platy particles of finite length immersed in 1:1 electrolytes is examined. The potential distribution around the plates are computed by solving the Poisson-Boltzmann equation with the aid of a finite difference numerical technique. The magnitude and location of the net repulsive force between the plates are then computed for a range of values of geometrical parameters and surface potential. The results indicate that as the angle between particles increases, the magnitude of repulsive force decreases very quickly, and the location shifts toward the closest ends. It is also shown that the force computed by a simplified method based on Derjaguin’s approximation compares reasonably well with that computed by the finite difference numerical method. The simplified method should provide a reasonable and fast means of computing repulsive force in semiquantitative analyses of colloidal systems consisting of platy particles.