Phytopathogenic fungi, which are leading to significant economic and production losses, pose a serious threat to global forestry. Field surveys were carried out on Eucalyptus trees in Ethiopia between 2019/20 and 2020/21. The E. camaldulensis predominantly grew in the surveyed fields and was severely affected by progressive stem canker disease. The diseased stems and branches exhibiting symptoms were collected, and the Lasiodiplodia theobromae and Neofusicoccum parvum fungal pathogens were identified via morphological and DNA sequence analyses of ITS1 and ITS2 from rDNA. The objective of this research was to assess the in vitro growth inhibition potential of Trichoderma species against Lasiodiplodia theobromae and Neofusicoccum parvum fungal species. Researchers are now exploring alternate eco-friendly management strategies due to the hazardous effects chemical fungicides have on human and environmental health. The use of biocontrol agents, such as Trichoderma species, is one of the potential approaches employed today. The antagonistic activities of Trichoderma asperellum (T4), Trichoderma asperellum (T5), Trichoderma atroviride (T1), Trichoderma atroviride (T11), Trichoderma longibrachiatum (T3), and Trichoderma longibrachiatum (T31) were tested in vitro against Lasiodiplodia theobromae and Neofusicoccum parvum that cause canker disease symptoms in E. camaldulensis. In all antagonism tests, T. asperellum and T. longibrachiatum effectively inhibited the growth of L. theobromae and N. parvum. This implies that the Trichoderma species could be useful to control E. camaldulensis canker disease.