Program-wide Positive Behavioral Interventions and Supports (PWPBIS), an early childhood extension of Positive Behavioral Interventions and Supports (PBIS), is a multi-tiered system of supports that has shown promise in fostering the social, emotional, and behavioral development of young children in preschool settings. The literature indicates that positive stakeholder perceptions of PBIS/PWPBIS may contribute to its overall success in early childhood and K-12 settings (Odom et al., 2005; Sugai et al., 2000). Given the gaps in the literature identified by this researcher associated with understanding stakeholder perceptions regarding social validity, barriers, and facilitating factors related to implementing PWPBIS across tiers, the purpose of the current qualitative study was to explore teacher and administrator perceptions of social validity, barriers, and facilitating factors associated with Tier 1 and Tier 2 implementation of PWPBIS within an urban early childhood program. Descriptive statistics and thematic analysis of survey and focus group data were used to report the experiences of teachers and administrators as well as compare and contrast the information provided by participants in each group. Findings suggest that teachers and administrators generally view the goals and outcomes of PWPBIS as socially valid across Tier 1 and Tier 2. Their satisfaction varied due to barriers such as inconsistent implementation, lack of staff buy-in, and time constraints. Successful implementation was facilitated by external support from a county-level agency, consistent implementation, and observing positive impacts of supports on students. Implications for research and practice within the field of school psychology are discussed to inform future practice. [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.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]