Research on how professional development has influenced teacher self-efficacy revealed that properly executed professional development promoted effective teacher practices and positive student outcomes. Bandura's and Tschannen-Moran's social learning theories were used in this basic qualitative study to address the problem of the lack of current investigations related to prekindergarten (pre-k) educators' perspectives regarding professional development that influenced their teacher self-efficacy. The research questions focused on pre-k educators' perceived characteristics of professional development that increased their confidence in their ability to be effective in the area of curriculum, classroom management, and motivating and engaging students. Findings from coding analysis of the data collected through online interviews with 10 pre-k educators revealed four themes: (a) effective professional development includes relevant implementation strategies, (b) effective professional development is presented by knowledgeable experts, (c) ineffective professional development lacks relevant and sufficient implementation strategies, and (d) ineffective professional development relies on redundant requirements. This study contributes to social change by augmenting the professional literature on this topic and possibly improving professional development implementation processes for school districts. [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.]