New materials for oxygen evolution reaction (OER) electrocatalysts in alkaline conditions have been highly investigated in recent years as an alternative to water splitting. However, questions such as the lack of stability and the use of noble metals as electrocatalysts still need to be addressed. We will describe materials based on natural wolframite (FexMn1−xWO4), exploring the impact of isotropic substitution of Ni and Mn cations on the electrochemical catalytic performance in the oxygen evolution reaction (OER). Fe0.5Mn0.5WO4, Ni0.5Mn0.5WO4, Fe0.5Ni0.5WO4, Fe0.5Co0.5WO4, and Co0.5Mn0.5WO4 were successfully synthesized through a hydrothermal reaction, characterized using X-ray diffraction analysis (XRD), and tested for their electrocatalytic properties towards OER in basic conditions (0.1 M KOH). Among the materials prepared, Ni0.5Mn0.5WO4 has shown the most promising activity, exhibiting ease of preparation, stability over the course of our experiments, and OER activity comparable to the standard iridium oxide. Additionally, solid solutions of NixMn1-xWO4 (x = 1, 0.9, 0.75, 0.6, 0.5, 0.4, 0.25, 0) were synthesized, and morphologies investigated through scanning electron microscope (SEM) and transmission electron microscopy (TEM). The optimal Ni/Mo ratio for electrocatalytic activity was determined to be 50%. This study contributes to the development of a new class of transition-metal-based heterofunctional catalysts for electrocatalytically splitting of water to produce O2.