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Studies of influence of forest cover on understorey species diversity, nutrient availability, soil moisture and microbial population abound in literature. However, little work has been done in lowland secondary forest in Ile-Ife, Nigeria. This study therefore examined the impact of forest cover on plant species diversity, soil nutrients and microbial population in Ile-Ife. Plants species encountered within 2m by 2m plot under forest cover and adjacent open area were counted and identified to species level. Floristic compositions, species distribution, species diversity indices (ShannonWiener index, Simpson’s Index and species evenness) were calculated. Composite soil samples were collected at the depth of 0-15cm, air-dried, sieved and analysed for soil pH, total N, C, cations (Na, K, Ca and Mg), available and total P. Microbial population was also considered. Results revealed that there were 49 species distributed into 28 families (293 individuals) under the tree cover, while there were 53 species distributed into 33 families (451 individuals) in the open vegetation. Soil physico-chemical properties such as pH, moisture, total N, C, P, available P, exchangeable cations (Mg, Na, Ca, and K), exchangeable acidity and soil moisture were also significantly higher  (p < 0.001) in the area under the cover. The count of bacteria (colony form) 6.12×105 - 4.09×106 and fungi (spores form) 7.07×105 - 5.31×106were also found to be significantly higher under the forest cover compared with the values for bacteria and fungi respectively (2.52×104 - 2.19×105and 8.57×102 - 4.32×103)   in the open area. The Jaccard index of similarity (79.49%) was high between the study sites. The result of this study showed that forest cover has a beneficial effect on soil properties and nutrient pool. Plants species richness and microbes population were also higher under the forest cover than in the open area. Species diversity and richness, soil nutrient, and microbial population were greatly influenced by forest cover. Keywords: lowland forest; microbial population; population; species diversity; forest cover.