The purpose of this research is to study the impact of effective professional development training provided to both preservice and inservice teachers about gifted education and gifted students. This research also seeks to discover whether a notable difference exists between preservice and inservice teachers in regard to the increase in their knowledge and self-efficacy upon completion of the professional development training. A quantitative approach using a survey and a required training was used for all participants. Study participants included preservice teachers attending a southern Kentucky public university who were taking education classes as well as inservice teachers from 11 school districts in Kentucky and one school district in Tennessee. Data were collected from the survey both before and after participants completed the training and then analyzed to ascertain participant gains for each of the research questions. The results from this study indicated the positive impact of the focused professional development training on all educators who participated. Both preservice and inservice teachers experienced gains in their knowledge of gifted education and gifted students, as well as in their confidence in the ability to meet the needs of these students in the classroom. The results further indicated gifted education professional development training should be provided to all preservice and inservice teachers to provide them with effective materials and strategies they can incorporate into their instruction. [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.]