Traditionally, sport has been a heteronormative domain space in which women and men with different sexual orientations have been rejected as transgressing and questioning the 'heteronormative patriarchy'. In recent years, Spanish society seems to have changed and a more tolerant and respectful climate of diversity has been created. However, there are no current studies analysing this situation in sport in Spain. In this work, an Attitude Scale towards Sexual Diversity in Sport is presented. The initial version of the 32 item questionnaire was completed by 414 athletes of both genders, whose ages ranged from 13 to 44 years old (M = 21.72, SD = 4.48). The validity of the content of the initial battery of items was analysed by four experts. Afterwards, two successive Exploratory Factor Analyses were carried out to assess internal validity determining a scale of 18 items and adequate internal consistency reliability (alpha =.904). The results also show that there are four factors that bring these attitudes together: Cognitive Attitudes towards diversity, Attitudes towards Gender Stereotypes, Attitudes towards Transgression and Affective Attitudes towards diversity. Item analysis and analysis of the internal consistency of the four factors were also carried out. Therefore, the study results support the conclusion that the scale, in general, shows good adaptation due to its validity and reliability.