Leary (1992) suggests a self-presentation perspective could fruitfully be applied to sport. In support of this, early research has revealed that self-presentation concerns underpin a large percentage of competitive anxiety and stress in sport (James & Collins, 1997; Wilson & Eklund, 1998). However, little progress has been made towards the identification of athletes who are most at risk of experiencing self-presentation concerns. The main aim of this thesis was to examine self-presentation concerns in athlete populations. More specifically, the aims were firstly to develop a valid measure of self-presentation concerns in sport. Secondly, the impact of gender, age, skill level and type of sport on self-presentation concerns was examined. To achieve these aims five studies, including three validation, one quantitative and one qualitative study, were conducted. The validation studies provided evidence to suggest that the Self-Presentation in Sport Questionnaire (SPSQ) is a valid and reliable measure of self-presentation concerns in sport, suitable for administration to athletes over the age of eighteen. However, shortened versions ofthe SPSQ, suitable for children and adults, demonstrated a weakened internal structure and consequently these instruments ought not to be administered in their present state. The quantitative study investigated the impact of gender, skill level and type of sport on self-presentation concerns in swimmers, water polo players and divers utilising the SPSQ. The findings indicated that females exhibit consistently higher self-presentation concerns compared to males, as do non-elite athletes when compared to the elite. Furthermore, self-presentation concerns were affected by the situation in different ways dependent on the athletes' gender. Finally, differences in the self-presentation concerns experienced in adolescence and adulthood were qualitatively assessed. Differences were identified across the type of self-presentation concerns experienced, the strategies used to make an impression, and the targets of self-presentation. Overall the research conducted provides a valid measure of self-presentation concerns in sport, which can be utilised in future self-presentation studies. Furthermore, the impact of a number of individual and situational variables on self-presentation concerns has been revealed.