This study investigated the factors enhancing invasion by L. camara (L.) and Eucalyptus species and their impacts on the indigenous woody tree species diversity and density at Khami. A vegetation survey of the species structure and composition of indigenous woody trees and exotic trees at sampled areas invaded and not invaded by L. camara and Eucalyptus species was done in order to determine their impact on the indigenous trees diversity and density. The results showed that L. camara and Eucalyptus sp. out competed indigenous trees significantly reducing their species richness, abundance, density and basal area. They both have a high water usage, which enable them to competitively displace indigenous trees. Eucalyptus sp. formed a closed canopy limiting light penetration and causing an increase in the height of the indigenous trees. L. camara releases chemicals (allelopathy) into the soil suppressing the regeneration of the indigenous trees. It is recommended that further research and monitoring be done to establish the rate of spread of the exotics in order to strategize and prioritize on their eradication and control on the varied ecosystems of Khami World Heritage Site.