Purpose: The purpose of this study was twofold: First, we replicated in a new sample our previous findings that a culturally and linguistically responsive (CLR) bilingual approach for English vocabulary instruction for preschool Latino dual language learners was effective. Subsequently, we investigated whether the positive effect of CLR instruction varies as a function of individual child characteristics, including baseline vocabulary levels and gender. Method: Using a randomized pretest-posttest follow-up group design, we first replicated our previous study (N = 42) with a new sample by randomly assigning 35 Spanish-speaking Latino preschoolers to a CLR bilingual group or an English-only group. The preschoolers received small-group evidence-informed shared readings targeting 30 English words 3 times a week for 5 weeks in their preschools. Vocabulary outcomes were measured using both standardized and researcher-developed measures. We subsequently conducted further studies with the combined sample size of 77 children to examine the variability in intervention effects related to child gender and baseline vocabulary levels. Results: The direct replication study confirmed findings of our earlier work suggesting that the CLR bilingual approach promoted greater gains in L1 and L2 vocabulary than in an English-only approach. The extension studies revealed that the effect of the CLR bilingual vocabulary approach on English and Spanish vocabulary outcomes was not impacted by gender or vocabulary status at baseline. Conclusion: This study provides additional evidence of the benefits of strategically combining L1 and L2 for vocabulary instruction over an English-only approach. Our findings also suggest that preschool Latino dual language learners can benefit from a bilingual vocabulary instructional approach regardless of gender or baseline vocabulary levels in L1. (author abstract)