In this study the in vitro anthelmintic and antioxidant activities of the plant Thespesia populnea were estimated using its ethanolic extracts. The effectiveness of the plant against parasitic diseases resulting from helminths was assessed. The plant samples were extracted using ethanol, and various constituents such as tannins, phenols, steroids, and glycosides were identified through a phytochemical screening. The extract exhibited antioxidant activity in the DPPH radical scavenging assays. In addition, the anthelmintic effect was demonstrated in vitro using earthworms. The effects of higher dosages were comparable to those of the well-known medication albendazole, which belongs to the benzimidazole class of anthelmintics. These results indicate that phytochemicals in Thespesia populnea have both anthelmintic and antioxidant effects, which may act synergistically or have cumulative effects.