Gal Oya National Park in Sri Lanka was established in 1954 and serves as the main catchment area for Senanayake Samudraya, the largest reservoir in Sri Lanka. An important feature of the Gal Oya National Park is its elephant herd that can be seen throughout the year. Three important herbs of the Ayurveda medicine, Triphala: Terminalia chebula, Terminalia bellirica, and Emblica Officinalis are amongst the notable flora of the forest.

32 terrestrial mammals have been recorded in the park. The Sri Lankan elephant, Sri Lankan axis deer, muntjac, water buffalo, Sri Lankan sambar deer, Sri Lanka leopard, toque monkey, and wild boar are among them. Included amongst the reptile species of the park are the mugger crocodile and star tortoise. More than 150 species of birds have been recorded in Gal Oya.