A dialogic storybook-based intervention integrating dialogic storybook reading with early literacy activities is studied with a longitudinal quasi-experimental study design. The effects of this intervention, in addition to a regular early childhood education (ECE) program, on kindergartners' vocabulary and phonological awareness development are analyzed for children from different backgrounds. Results indicated that the intervention may be effective in stimulating expressive vocabulary development. With regard to receptive vocabulary and phonological awareness measures, the intervention seems to have a similar effect to using a regular ECE program. The intervention had a similar effect for all children. Findings suggest that an active participation, in which the children are encouraged to talk about language, seems to be beneficial to enhance children's language use; this aspect might be elaborated in existing or future ECE programs. The intervention can be used to help children from underprivileged families to gain language skills to ensure an optimal start of formal education in Grade 1.