Females of the Strawberry Poison Frog (Oophaga pumilio) are known to be aggressive toward other females. However, the function of this behavior in females has not been identified. We hypothesized that females are territorial, occupying and defending specific areas in defense of food resources. To test this hypothesis, we calculated the position and size of core areas and home ranges for each female in the study area and the frequency of aggressive and feeding behavior exhibited by females in these areas. We provide evidence, for the first time, that females are territorial; they defend their core area against other intruding females. To determine the potential resource defended by females, we examined aggressive behavior associated with defense of mates, oviposition, and tadpole-rearing sites. We found no evidence that females defended areas with males, or that oviposition and tadpole-rearing sites were limited and defended by females. Instead, our observations suggest that female territoriality is most likely associated with the defense of feeding areas.