The development of a self-report instrument to measure antisocial sport behavior, labeled the Antisocial Sport Behavior Survey (ASBS), among large and diverse samples of athletes is reported. Grounded in the social cognitive theory of moral thought and action (Bandura, 1991) and interpersonal theory (Horowitz, 2004), this instrument was developed and tested in accordance with the traditions of construct validity and classical test theory (Gehlback & Brinkworth, 2011). In Phase 1, 272 college-aged competitive sport participants confirmed a theoretical structure of antisocial sport behavior including eight factors (hypercompetitive, intimidating, antagonistic, disrespectful, exploitable, overly accommodating, abetting, and melodramatic). Phase 2 reports on item development and the response structure of the instrument. In Phase 3, evidence of structural validity and external validity for the ASBS was established with 340 college-aged competitive sport participants. The ASBS presents as a promising new instrument to advance understanding of antisocial sport behavior acts committed by competitive athletes.