The mixed methods study aimed to measure the impact professional development programs have on STEM professionals' job satisfaction and organizational commitment, specifically, through the level of participation in the professional development program, and employees' perceived effectiveness of said professional development program. Four research questions and their corresponding null and alternative hypotheses guided the quantitative portion of this study. These research questions were designed to investigate the associations between level of participation in professional development programs and STEM professionals' perceived effectiveness of organizational professional development practices as the independent variables and job satisfaction and organizational commitment as the outcome variables. The results supported to reject all four null hypotheses. These findings suggested that participation in PD was significantly negatively associated with both job satisfaction and organizational commitment, indicating that as level of participation in PD increases, typically, both job satisfaction and organizational commitment levels tend to decrease. The results also showed that perceived effectiveness of organizational professional development practices was significantly positively associated with both organizational commitment and job satisfaction. These findings suggested that higher levels of perceived effectiveness of organizational professional development practices were associated with higher levels of job satisfaction and organizational commitment. This study serves as a model for how organizations can gain valuable information from their employees about the impact of such programs, regardless of industry or organization. Once they can obtain employee perspectives, organizations can implement new policy and strategies that provide worthwhile professional development opportunities to promote job satisfaction, organizational commitment, and career self-efficacy. [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.]