This study carried out to examine electrocatalytic activity of Ni–Mn–Sn alloy foams for oxygen evolution reaction (OER) in alkaline media. As the first step, Ni–Mn–Sn alloy foams were prepared of sulfate bath on copper substrate. Next, after optimization of electrodeposition condition by cyclic voltammetry (CV) test, foams were electrodeposited at different current densities 100, 120, 140 and 180[Formula: see text]mA[Formula: see text]⋅[Formula: see text]cm[Formula: see text]. Then, they were characterized by field emission scanning electron microscopy (FE-SEM) along with energy disperse x-ray spectroscopy (EDS) to investigate surface morphologies and chemical compositions. According to FE-SEM results, it was revealed that formation of foam like structures were due to the presence of dynamic hydrogen bubbles template (DHBT). To survey their structure, grazing incidence X-ray diffractometer (GIXRD) analysis was performed. The resulted diffraction pattern determined not only FCC nickel structure of foams, but also mixed phases composed. Following this, Ni–Mn–Sn alloy foams were placed in 0.1 M KOH and related CV tests were applied to measure their electrocatalytic activity for OER. This study demonstrated good electrocatalytic activity for Ni–Mn–Sn alloy foams by showing favorable oxygen evolution overpotenitals and Tafel slopes.