Measures of productivity and sentence organization are useful metrics for quantifying language development and language impairments in monolingual and bilingual children. It is not yet known what measures within and across languages are most informative when evaluating the language skills of bilingual children. The purpose of this study was to evaluate how measures of language productivity and organization in two languages converge with children's measured language abilities on the Bilingual English Spanish Assessment (BESA), a standardized measure of language ability. 170 kindergarten age children who produced narrative language samples in Spanish and in English based on a wordless picture book were included in the analysis. Samples were analyzed for number of utterances, number of different words, mean length of utterance, and percentage of grammatical utterances. The best predictors of language ability as measured by the BESA scores were English MLU, English grammaticality, and Spanish grammaticality. Results are discussed in relationship to the nature of the measures in each of the languages and in regard to their potential utility for identifying low language ability in bilingual. Learning outcomes: The reader will be able to identify (1) why narratives are useful for evaluating bilingual language ability, (2) which measures of productivity and sentence organization in narratives best capture language ability and development in bilingual children, (3) how a bilingual or composite language ability across two languages can be determined, and (4) what relationship exists between measures of productivity and sentence organization in each language with a bilingual language ability score. (Contains 7 tables.)