This mixed method research study examined the extent adjunct professors teaching online have applied best online teaching practices, as defined in Laurillard's Conversational Framework, and how they perceived professional development impacted those teaching practices. A purposeful sampling of online adjunct instructors in two Facebook groups, "Making a Living Teaching Online" and "Adjunct Professors Unite" was conducted to collect the quantitative survey data then volunteer online adjuncts from the survey takers were selected for a qualitative interview portion of the mixed method study. The researcher received permissions to modify a validated survey instrument. An online thirty question instrument was developed and administered through Qualtrics™ program. Data analysis was conducted using descriptive and inferential statistics, along with Microsoft Excel for qualitative interview coding and IBM® SPSS Statistics 27 analytic software for quantitative survey data analysis. The relationships between the dependent variables and independent variables were analyzed using descriptive and inferential statistics to include regression, correlation, t tests, and ANOVAs. Results of this study were analyzed to determine the relationship of faculty who teach online and the extent to which they perceive the impact of professional development on their online teaching. Qualitative and quantitative results indicated that there is a positive relationship between online teaching practices and perceived impact of professional development for adjunct instructors. [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.]