This study identified qualities of influential facilitators of elementary mathematics professional development. Extensive research relating to elementary mathematics professional development has emerged over the past three decades. Embedded in this body of research are recommendations for effective practices in professional development and examinations of models that have utilized these effective practices. However, little emphasis has been placed on the role of the facilitator in professional development for elementary mathematics. A phenomenological design was utilized to determine how twenty United States elementary school teachers characterized influential facilitators of professional development. Emerging themes indicate teachers in this sample perceived influential facilitators along five themes: (1) Credibility, (2) Support, (3) Motivation, (4) Management, and (5) Personality. Based on these findings, a multiplicative effect is introduced as a potential framework for increasing teacher motivation during professional development. (Contains 1 figure and 7 tables.)