Background: A promising method for improving physical inactivity among women is to increase their engagement in group-based exercise programs. Fitness communities are exercise groups that practice the principles of group dynamics and promote a lifestyle of physical activity by engaging members through social media and hosting social event/hangouts outside of the gym or "fitness" setting. Purpose: The purpose of this study was to examine the role of "fitness communities" as a mechanism for increasing engagement in physical activity. Methods: In-depth, semi-structured interviews (N = 15) from women who were members of an established fitness community (i.e. Titan Fitness; the original name has been changed for purposes of anonymity) in Southern California. Results: Results suggested that the women's experiences in Titan Fitness were encompassed by six sub-themes which were the following: "Structured Exercise Classes with Group Dynamics": (1) personal and group accountability and (2) minimizing intimidation; "Social Media Engagement": (3) empowerment and (4) accountability via online engagement; and "Engagement Outside of the Physical Gym Setting": (5) in-group engagement and (6) out-group (extended) engagement. Discussion: Our findings illustrated that community members that were engaged in all three components of a fitness community described improved physical activity adherence. Translation to Health Practice: These findings may benefit fitness professionals, researchers, and Health Education practitioners who desire to develop innovative theoretically-based interventions for women having difficulty with physical activity adherence.