ABSTRACT This study examines the influence of relatedness to emotional brand attachment, specifically in the context of Self-Determination Theory. It aims to fill the extant literature regarding a mini theory of Self-Determination Theory (SDT), Relationship Motivation Theory (RMT), which has not been examined in the communication and marketing literature. The study identifies which dimension(s) of relatedness – defined as Acceptance/Support, Connection, Common Interests, and Congruity – are predictors of Emotional Brand Attachment (EBA), specifically in the context of fitness-related non-profit organizations. By use of a survey to fitness-related non-profit supporters, this formative research endeavors to investigate a yet untested facet of emotional brand attachment in a communication and branding context. The scope of this research is not limited to merely predictors of Emotional Brand Attachment under the SDT framework, but also ventures to inform the communication literature so non-profit executives and marketers can more strategically and effectively craft messaging to foster EBA.