The development of anthelmintic resistance and the high cost of conventional anthelmintics have led to the evaluation of medicinal plants as an alternative source of anthelmintics. In the current study, in vitro experiments were conducted to determine the possible anthelmintic effects of Balanites aegyptiaca stem bark aqueous extract on Strongyle larvae and the earthworm Pheretima posthuma. The in vitro studies revealed that the extract at graded concentrations of 300 mg/ml, 400 mg/ml, 500 mg/ml and 600 mg/ml exhibited larvicidal activity (p<0.05) against earthworms with 600 mg/ml having the highest activity causing paralysis and death. In a similar vein, a graded concentration response was observed against Strongyle larvae. The highest effective concentration on larvae was 250 mg/ml which had a larval mortality rate of 100% and a mortality index of one (1) comparable with that of albendazole. The IC50 and IC99 values for the time of paralysis were 442.7mg/ml and 767.80mg/ml respectively. The anthelmintic activity exhibited by the extract could be linked to the presence of phytochemicals present in the plant. These findings support the folkloric use of this plant in the control and management of gastrointestinal nematodes in humans and animals.