In this study, I examined the main and interactive effects of attribution dimensions on efficacy expectations in sport. A sample of 162 athletes (102 males, 60 females) aged 20.9 years (s = 3.4) from various sports were recruited. The participants, who were of club to international standard, completed the Causal Dimension Scale II (McAuley et al., 1992) in relation to their most recent performance. They then completed a 7-item measure of efficacy expectations in relation to their upcoming performance. The key predictors of efficacy expectations were stability and personal control, but their function differed after more or less successful performances. After more successful performances, attributions to stability and personal control were associated with main effects upon efficacy expectations, in a positive direction; after less successful performances, attributions to stability and personal control were associated with an interactive effect upon efficacy expectations. The form of this effect was such that the participants were more likely to have high efficacy expectations only when they viewed the cause of their performances as both personally controllable and stable.