The purpose of this quantitative, correlational study was to investigate the relationship between parent and child temperament on language acquisition as well as the relationship between parent responsivity and parent-child temperament in autistic children. Participants were 25 parent-child dyads of autistic children between the ages 2 and 8 years of age (18 boys, 7 girls). Parents provided ratings of their temperament and their child's temperament. The child's expressive language, receptive language, and receptive vocabulary were assessed by a licensed speech-language pathologist. Parents' engagement with their children were rated by undergraduate research assistants blind to the study using a Likert rating scale for parent-responsive behaviors. There were several significant findings in the 2-year-old and 3- to 6-year-old age groups. In the 2-year-old age group, significant correlation coefficients were found for the associations between adult effortful control and the autistic child's language, child extraversion and their language, parent responsivity and adult extraversion and negative affect, and finally parent responsivity and child effortful control. Then in the 3- to 6-year age group, there was a significant positive correlation between the autistic child's negative affect and their expressive language. Lastly, in the 7- to 8-year age group, there was a near significant association between adult effortful control and the autistic child's language. Overall, these findings indicate the importance of identifying the parent's and child's temperament and the impact both have on the autistic child's language and their parent's responsive behaviors to enhance the therapy model and improve relationships to maximize the child's ability to acquire language. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]