Prader-Willi syndrome (PWS) is a rare genetic disorder that adversely impacts child development and health conditions, and is often associated with significant behavioral challenges. In particular, children with PWS typically exhibit extremely high levels of maladaptive behavior (e.g., excessive food seeking, hording, and binging; temper tantrums; aggression; stubbornness; and obsessive and compulsive behaviors). Child maladaptive behavior has been demonstrated as predictive of parent stress across many developmental disabilities and child conditions. However, prior to this study, there have been few studies, specifically describing the child behavior and parent stress relationship for families with children with PWS. Research has also indicated that, for other developmental disabilities, parent perceptions regarding received support are correlated with reductions in parent stress. However, prior to this study, there has been no current research documenting parental perceptions of the type and frequency of support received in the PWS population, nor have there been any current studies exploring the complex relations between support, child maladaptive behavior, and parent stress in parents of children with PWS. This study addressed these noted gaps in the literature by: (1) investigating parent perceptions of the availability and helpfulness of educational, professional, social, and informational support sources; (2) examining whether or not parents perceive some sources of support to be more helpful than others; and (3) investigating the relations between educational, professional, social, and informational support, challenging child behavior, and parent stress in a sample of 61 biological parents (predominantly mothers) of children with diagnosed PWS. Findings indicated that parent perceived several individual support sources as particularly helpful, such as spouses/partners and supports that were idiosyncratic to PWS (i.e., PWS Foundations, Associations, and Clinics). In addition, for support sources that were utilized by greater than 40% of the sample, parents did not perceive any support source category (i.e., educational, professional, social, informational) as more helpful than any other. Child maladaptive behavior was predictive of parent stress, and sources of support by category (i.e., educational, professional, social, and informational) were not predictive of parent stress. [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://www.proquest.com/en-US/products/dissertations/individuals.shtml.]