The derivation and implementation of natural switching surface (NSS) control for a flyback converter operating in boundary conduction mode (BCM) is the main focus of this paper. The flyback converter has been wildly utilized in the area of power electronics and BCM operation has been proven to be successful in attaining high efficiencies. The NSS presents many benefits for the control of non-linear systems such as fast transient response under load-changing conditions. The NSS control technique has previously been implemented in non-isolated (e.g., buck and boost converters) and isolated (dual active bridge) converter topologies demonstrating excellent performances. The analytical derivation of the proposed switching surfaces is presented and validated through simulations using MATLAB/Simulink™ and a 65W prototype was experimentally tested.