Previous research in child language shows that many aspects of language acquisition are frequency-linked. This study tests whether input or usage frequency predicts the order of acquisition and accuracy of a bilingual Greek-English child's English possessives. The child was followed longitudinally from age 2;6 to 3;11. Order of acquisition was comparable to that of same-aged monolingual children. The child's usage frequency and order of acquisition were highly correlated with input frequency, while her accuracy was not. We argue that the child's already-acquired Greek possessives facilitated acquisition of English possessives, even though the child's English input and usage frequencies were lower than in monolingual English children.