Manganoferrous (Fe-Mn) oxide ores represent important mineral resources owing to their applications in metallurgical industries and their growing significance as potential sources of critical raw materials. In this study, a manganoferrous (Fe-Mn) oxide ore collected from the Şırnak region of southeastern Türkiye was comprehensively characterized using X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM-EDS), elemental mapping, Fourier-transform infrared spectroscopy (FT-IR), and thermogravimetric–differential thermal analysis (TG-DTA-DTG). XRD analysis identified quartz (SiO₂), goethite [FeO(OH)], and bixbyite [(Fe,Mn)₂O₃] as the major mineral phases present in the ore. XRF results revealed that the sample contains approximately 49.3 wt.% Fe₂O₃, 14.6 wt.% MnO, and 18.6 wt.% SiO₂, indicating a manganoferrous (Fe-Mn) oxide ore or sub/low-grade ferruginous manganese ore characterized by significant iron enrichment and moderate manganese content. SEM-EDS and elemental mapping analyses demonstrated heterogeneous mineral distribution and a strong spatial association between iron and manganese oxide phases. FT-IR spectroscopy confirmed the occurrence of hydroxyl-bearing iron oxyhydroxides, mixed Fe-Mn oxide minerals, and silicate gangue through characteristic O–H, Fe–O, Mn–O, and Si–O vibrational bands. TG-DTA-DTG analysis revealed multi-stage thermal decomposition behavior with an overall mass loss of approximately 11.9 wt.%, primarily attributed to dehydration and dehydroxylation reactions associated with goethite-bearing phases. The findings provide valuable mineralogical and thermal information for future beneficiation, reduction roasting, magnetic separation, and hydrometallurgical processing studies involving ferruginous manganese ores from southeastern Türkiye.