This study investigated the physical and chemical properties and aluminum (Al) oxide dynamics in soils across four agro-ecological zones of Southwestern Nigeria: NIFOR (Coastal Plain Sands), Uhonmora (Shale), Idanre (Basement Complex), and Koko (Hydromorphic). Composite soil samples were collected at depths of 0–30 cm, 30–60 cm, 60–90 cm, and 90–120 cm to analyze pH, organic carbon (Org C), nitrogen (N), phosphorus (P), exchangeable cations, texture, and Al oxide forms (crystalline, amorphous, organically bound). Results revealed significant variations in soil properties driven by parent material. Acidic soils dominated Koko (pH 4.43–4.8) and NIFOR (Rhodic Paleudult), while Idanre’s near-neutral soils (pH 5.77–6.23) reflected Basement Complex weathering. Organic carbon and nitrogen declined with depth, with surface layers (0–30 cm) retaining the highest values (e.g., Uhonmora: Org C 10.43 g kg⁻¹). Phosphorus availability was higher in shale-derived (Uhonmora: 7.72–14.48 mg kg⁻¹) and Basement Complex soils (Idanre) due to mineral apatite. Aluminum oxides exhibited parent material-specific trends: crystalline Al (DCB-Al₂O₃) dominated shale soils (Uhonmora: 3.01–3.23 mg kg⁻¹), while hydromorphic soils (Koko) accumulated organically bound Al (P-Al₂O₃: 0.03–0.44 mg kg⁻¹). Coastal Plain Sands (NIFOR) showed mixed Al sources, with sandy textures promoting leaching. Correlations highlighted organic matter’s role in binding Al (P-Al₂O₃–Org C: r = 0.965 in NIFOR) and clay’s influence on oxide retention. These findings underscore the need for location-specific soil management to address Al toxicity, nutrient deficiencies, and sustainable land use in Nigeria’s diverse agro-ecosystems.