The objective of this thesis was to examine the relationship between achievement goal orientations and motivational climate in sport contexts. Specifically, the research aimed to examine how complimentary versus conflicting motivational climates might interact with athletes' dispositional goal orientations. Reservations over existing measures of achievement goal orientations lead to the development of a new measure of achievement goals. The first study investigated the structural integrity of a four-goal model of achievement goal orientations utilising confirmatory factor analysis and explored the concurrent validity of the four-goal model with an existing measure of achievement goal orientations. The second study examined the predictive validity of the four-goal model of achievement goals explored in study one with regards to a process focus in rugby union players. The third study examined the influence of the interaction between motivational climate and achievement goals, using an existing measure of achievement goals, on motivation and tension. The final study examined the influence of the interaction between motivation climate and achievement goals, using the four-goal measure of achievement goals developed in study one, on motivation and tension. Results indicated that: (a) the 20-item, four-goal model of achievement goals possessed very good factor structure, good concurrent and predictive validity, but that the four factors had relatively high factor-factor correlations; (b) self-directed task was a strong predictor of a process focus; ( c) in a strong performance climate, athletes with high levels of ego orientation had high levels of self-determined motivation; ( d) in a strong mastery climate, athletes with low levels of ego orientation had high levels of self-determined motivation; (e) in a strong performance climate, high levels of self-directed ego orientation and low levels of social approval ego orientation appear to be beneficial for self-determined motivation; and (f) in a strong mastery climate, high levels of self-directed ego orientation and social approval task orientation appear to be beneficial.