Li-ion batteries have revolutionized modern life by enabling the widescale utilization of portable electronic devices and electric vehicles. However, lithium is a scarce resource, therefore utilizing more abundant sodium in Na-ion batteries is crucial to the future dependence of sustainable energy sources. Weberites (Na₂M^IIM^IIIF₇) are a fascinating class of structures to study as potential cathode materials because of their high structural stability, low 3-D Na-ion diffusion barriers, and wide chemical composition range. Until now, only Na₂Fe₂F₇ has been electrochemically studied and was shown to have remarkably high energy density, cyclability, and rate performance. In an effort to increase the energy density and improve the electrochemical performance of the material, we have created a series of Na₂Mn_xFe_2−xF₇ (x between 0 and 1) compounds based on both Mn²⁺/Mn³⁺ and Fe²⁺/Fe³⁺ redox. We have synthesized these materials through mechanochemical synthesis followed by an anneal, and have used X-ray diffraction and the Rietveld method to evaluate whether we successfully synthesized our desired material. Following synthesis, we galvanostatically cycled the materials against Na metal in Swagelok cells to retrieve capacity and voltage data that enables us to understand its electrochemical performance. We have found that by increasing the amount of manganese, the stability of the material is decreased leading to longer ball-milling times being needed. In addition, we have replicated similarly high energy density and cyclability as previously demonstrated for Na₂Fe­₂F₇, and have evaluated the electrochemical behavior of new mixed Fe and Mn weberites. These results further suggest that weberite Na₂Mn_xFe_2−xF₇ (x between 0 and 1) materials are very promising cathode materials for Na-ion batteries.