Soil organic and inorganic carbon fractions play a critical role in soil fertility, microbial activity, and carbon sequestration. However, land use changes and soil depth variations significantly influence these carbon fractions. This study investigated the effects of different land use types and soil depth on soil organic carbon and inorganic carbon fractions in Ondo State, Nigeria. A 5 × 3 factorial experiment was laid out in a Randomized Complete Block Design (RCBD), consisting of five land-use types (oil palm plantation, cocoa plantation, mango plantation, forest land, and arable land) and three soil depth levels (0-10 cm, 10-20 cm, and 20-30 cm) was carried out at the Federal University of Technology, Akure. Soil samples were collected from the Teaching and Research Farm of the Federal College of Agriculture, Akure, Ondo State. Various carbon fractions, including microbial biomass carbon (MBC), particulate organic carbon (POC), and SOC, were analysed using standard laboratory procedures. Results indicated that forest land and oil palm plantations had the highest SOC levels, while arable land exhibited the lowest. A significant decline in SOC was observed with increasing soil depth, with the highest levels found in the top 0-10 cm layer. MBC was highest at 10-20 cm and 20-30 cm depths, suggesting favourable conditions for microbial activity in these layers. The study concludes that land use management practices that promote organic matter accumulation, such as agroforestry, are essential for enhancing soil carbon storage and microbial health. Recommendations include adopting conservation agriculture practices to mitigate the adverse effects of intensive tillage on soil quality.