We study, in the framework of the entanglement harvesting protocol, the entanglement harvesting of both a pair of inertial and uniformly accelerated detectors locally interacting with vacuum massless scalar fields subjected to a perfectly reflecting plane boundary. We find that the presence of the boundary generally degrades the harvested entanglement when two detectors are very close to the boundary. However, when the distance between detectors and the boundary becomes comparable to the interaction duration parameter, the amount of the harvested entanglement approaches a peak, which even goes beyond that without a boundary. Remarkably, the parameter space of the detectors’ separation and the magnitude of acceleration that allows entanglement harvesting to occur is enlarged due to the presence of the boundary. In this sense, the boundary plays a double-edged role on entanglement harvesting, degrading in general the harvested entanglement while enlarging the entanglement harvesting-achievable parameter space. A comparison of three different acceleration scenarios of the detectors with respect to the boundary, i.e., parallel, anti-parallel and mutually perpendicular acceleration, shows that the phenomenon of entanglement harvesting crucially depends on the acceleration, the separation between two detectors and the detectors’ distance from the boundary.