This study investigated parents’ backgrounds and their beliefs about English language learning, and comparedthe receptive English vocabulary development of three to six year-old-Thai children before and afterparticipating in a parent-child reading program with the dialogic reading (DR) method. Fifty-four single parentsof 54 children voluntarily participated in the study. The parents were surveyed to determine if their demographicdata, beliefs, and DR method affected their children’s vocabulary development. The children were tested onfourteen English words before and after participating in the program. The results showed that parents’ beliefsabout English language learning affected expectations on their children’s language success. In addition, thechildren’s achievement was related to the use of DR method. The children yielded significant greater gains inknowledge of vocabulary and their ability to infer the meanings from pictures after engaging in the readingprogram.