Mutual coupling between antennas is undesirable in a variety of constellations including antenna arrays, smart antennas, multiple-input multiple-output (MIMO) systems, and independent antennas installed in a close proximity of each other due to real estate constraints. In the latter case transmission by one of the antennas (termed the aggressor) may desensitize the other antenna receiver (termed the victim). Thus, in many cases signal-processing techniques are inefficient in mitigating the adverse consequences of mutual coupling. In this work, we examine a configuration comprising three antennas, viz., a transmitting aggressor, a receiving victim, and a parasitic resonant element. The latter is designed to reduce the coupling between the aggressor and the victim. In our study, the parasitic antenna is a small size resonant structure located in a close proximity to a victim antenna. The parasitic element is strongly excited by the aggressor’s radiation at frequencies close to its self-resonance. This resonant element is designed to cancel the radiation from the aggressor at the location of the victim through strong near fields thanks to its close proximity to the victim. On the other hand, due to its small size, the parasitic element is an inefficient far-field radiator thus producing minimal variations in the radiation patterns of both the aggressor and the victim. As an example, we study coupling reduction between two monopole antennas by means of a small parasitic loop antenna. Approximate analytic model and numerical simulations are used to demonstrate the efficacy of the proposed technique.