Storybook reading has been used successfully to enhance language and vocabulary development of young children, however, there is limited research on the impact of storybook reading on lexical acquisition in dual language learning (DLL) preschoolers. Because lexical knowledge in preschool is a reliable predictor of succeeding literacy skills, this study compared the effectiveness of language of vocabulary instruction during shared storybook reading, on lexical acquisition, in typically developing DLL preschoolers. This switching replication study was guided by the following question: Does English instruction enhanced with Spanish bridging yield greater results in lexical acquisition than English-only vocabulary instruction, during a storybook reading intervention, in DLLs, ages three to five years? Data was collected from 14 typically developing Spanish-English bilingual preschoolers; six males and eight females. The participants were randomly assigned to one of two conditions: bilingual vocabulary instruction or English-only vocabulary instruction; however, on the second half of the study, the groups were interchanged. The intervention consisted of shared storybook reading. Outcome measures included expressive and receptive researcher-made measures of target vocabulary that were administered before and after the intervention. Data was recorded and analyzed using Independent Samples T-Tests. Results reveal that there was significant vocabulary growth between pretest and posttest scores. In addition, results indicate that bilingual vocabulary instruction results in slightly greater lexical acquisition. These findings provide additional evidence that shared storybook reading, particularly when combined with Spanish, facilitates English lexical acquisition in DLLs.