Description: Performance-avoidance goals (the desire to avoid performing more poorly than others) have been shown to have consistently deleterious effects on different outcomes including performance but the effects of performance-approach goals (trying to outperform others) are more complex (for a discussion of this point, see Harackiewicz, Barron, Pintrich, Elliot, & Thrash, 2002). Two studies examined uncertainty as a moderator of the effect of performance-approach goals on learning. Experiment 1 showed that manipulated performance-approach goals led to better learning than performance-avoidance goals in the absence of uncertainty about performance, but that when participants learned that a co-actor disagreed with them about problem solutions, uncertainty was enhanced, and performance-approach goals did not differ from performance-avoidance goals in their effect on learning. Experiment 2 showed that uncertainty also moderated the effects of self-set performance-approach goals. Moreover, it indicated that the same dynamic happens with another kind of uncertainty: negative competence feedback. These results confirm that in some contexts, performance-approach goals have positive effects on learning. They also underline that when uncertainty is enhanced, they loose their benefits and can become detrimental to learning.