Parasitic nematodes of the digestive tract remain one of the main constraints in small ruminants in subtropical countries. In these regions there are a lot of browsed plant species with antihelmintic activity; in this way an experiment was conducted to evaluate the effects of 2 lyophilised aqueous extracts of Lysiloma acapulcensis (LAE) and Phitecellobium dulce (PDE) tree leaves on in vitro assessment of hatching of eggs, larval development and migration of gastrointestinal nematodes of sheep using a general linear model. Treatments contained extracts from both species at concentrations of 0, 125, 250 and 500 µg/mL. Both albendazole and levamisole were used at a level of 1% as positive control. The extract of LAE, compared with PDE, showed better inhibition (P < 0.05) of egg hatching. Different doses of both the LAE and PDE extracts showed a larvicidal effect (P < 0.05) on all larvae exposed to different doses of the extracts. In the larval migration assay, a similar effect with levamisole occurred with the LAE extract at doses of 250 and 500 µg/mL. The extract of P. dulce had a lower larvicidal effect (P < 0.05) than levamisole and L. acapulcensis extracts. The use of aqueous extract of L. acapulcensis could be a promising alternative to synthetic anthelmintics as treatments of gastrointestinal nematodes of sheep in organic and conventional production systems under subtropical conditions.