Objectives: To develop and validate the Psychobiosocial Experience Semantic Differential scale in sport (PESDSport), a new measure to assess discrete emotions and performance-related experiences in sport as conceptualized within the individual zones of optimal functioning (IZOF; Hanin, 2000, 2007, 2010) framework. Method: In Study 1, we developed a preliminary 53-item version of the scale using a semantic differential format in the construction of the items pertaining to 12 psychobiosocial modalities. We chose this format to attain a clear representation of psychobiosocial states between opposites along perceived performance functionality (i.e., functional, dysfunctional). The preliminary scale was then administered in a sample of 280 athletes. In Study 2, a 30-item scale derived from Study 1 was cross validated in a second independent sample of 302 athletes. Results: Findings from Study 1 provided preliminary evidence of factorial and construct validity for a 10-modality, 30-item model (3 items for each modality). Findings from Study 2 supported the factor structure of a model containing 30 items loading into 10 modalities (i.e., unpleasant/pleasant emotions, confidence, anxiety, assertiveness, cognitive, bodily-somatic, motor-behavioral, operational, communicative, and social support). Convergent, discriminant, and nomological validity of the PESD-Sport was also demonstrated. Conclusion: Based on a substantive theoretical framework, this new measure of discrete emotions and performance-related experiences can advance the knowledge on the relationship between psychobiosocial states and performance. The scale could also inform applied interventions aimed at improving psychobiosocial experiences for performance enhancement.