Professional development (PD) hours are required for licensure renewal for the more than 110,000 teachers in Ohio. Despite being entrenched in the culture of education; many teachers view PD negatively. In this qualitative study, three structures of PD are studied to determine their impact on teacher attitudes. These three structures are online learning modules, professional conference/self-guided PD, and cohort/professional learning communities (PLC). The PD models are analyzed through the theoretical framework of andragogy, or the adult learning theory. There are six principles of andragogy, and these ideas were central to the questions in both a Google Form survey and semi-structured interview questions. There were 76 survey participants that fit the criteria of an Ohio teacher that had been through the licensure renewal process at least once and had engaged in all three models of PD being studied. Six of these participants were chosen to be interviewed via Zoom to gather more in-depth explanations as to why they answered the survey questions the way they did. The research determined that the more aligned to the principles of andragogy the PD structure is, the more positively it is received by the teachers. Conferences/self-guided PD were viewed most positively, followed by cohort/PLCs, and finally online modules; the first encompassed all six of the tenets of andragogy, cohort/PLCs included five out of six, and online modules comprised only one of the principles. This research has implications for those that plan and execute PD, especially at the district level. To elicit positive attitudes toward professional development, the model employed should prioritize the principles of andragogy. [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.]