Two-dimensional (2D) electrode materials present opportu-nities to enhance the efficiencies of electrochemical processes involved in electrocatalytic reactors, batteries, and super -capacitors. In this review, we discuss the theoretical basis of classical and quantum confinement effects, including how they modulate the performance of 2D electrode materials, in the light of recent experimental advances in the area. In particular, we discuss ion transport in the interstitial channels of 2D layers with and without spacers, the mechanisms and the underlying theories of mass and electron transport, and the effect of step edges, defects, and dopants on the mechanism and kinetics of electron transport in 2D electrode materials. We identify several opportunities for future work involving first-principles calculations, molecular dynamics simulations, and the devel-opment of analytical theories. Overall, this article not only provides a brief theoretical overview of electrochemical phe-nomena in 2D electrode materials, but also details several knowledge gaps in the field.