This study aimed at evaluating Matisaa gray rock (MGR) for clinker production. MGR is naturally abundant in Matisaa, a rural area in Mwingi West District, Kitui county, Kenya. It is locally used as a gabion filler and other concrete structures with desirable physico-mechanical properties. This research employed a controlled experimental design to determine the clinker qualification of MGR. This was based on particle size analysis and raw meal moduli. The standard sieve tests and a Blaine meter were used in the determination of particle size while the raw meal moduli were determined from the respective cement oxides in MGR, which were determined using wavelength dispersive X-ray fluorescence (WDXRF) spectrometer. It was observed that 69.65% of the particle size composition of MGR was less than 90 . Out of this composition, 71.60% of the particle sizes were less than 45 , contributing to a specific surface area of 292.5 . The hydraulic modulus (2.05 – 2.61) and lime saturation factor (0.87 – 0.98) are quite desirable though the silica and alumina ratios are higher than the standard range due to the low proportions of and content. The sulfatisation modulus is also undesirable due to the high content of . Thus, without beneficiation, Matisaa gray rock would lead to the production of low-quality clinker. However, the general parametric comparison of Matisaa gray rock with Konza shows that it has the potential for utilization as a clinker raw material.