Guided by the ironic process theory and its extensions, the dissertation research aimed at (a) studying the thought suppression paradox in student athletes, (b) exploring the efficacy of an acceptance-mindfulness intervention in decreasing the thought suppression paradox, and (c) using working memory capacity (WMC) to explain individual differences on the susceptibility to the thought suppression paradox. A total of 90 NCAA Division I student athletes were recruited and randomly assigned to three conditions (i.e., suppression, control, and intervention). All the athletes performed a set of computerized complex span tasks (i.e., operation, reading, and symmetry span), and then completed a task pair in each of the two thought-control phases (i.e., amid, post). The task pair consisted of a thought-monitoring task and a two-color Stroop task. According to the condition assignment, each athlete applied a strategy for controlling the thought of a recent athletic failure when performing the task pairs, and his/her EEG was simultaneously recorded. Results generally supported the existence of thought suppression paradox and the efficacy of an acceptance-mindfulness intervention in student athletes, although WMC failed to account for individual differences. Theoretical and applied implications are discussed.