ABSTRACT Two experiments investigated claims for the efficacy of self-deceptive coping (e.g., Sackeim, 1983, 1988). In Study I the performance of self-deceivers on solvable anagrams was found to he remarkably poor relative to that of non-self-deceivers after both groups were exposed to unsolvable problems. The starkly unambiguous failure experience may have precluded self-deception. Therefore, in Study 2 participants were exposed to unsolvable problems either with or without an excuse. Self-deceivers who encountered failure with an excuse subsequently performed much better on the solvable tasks than those without an excuse. These findings suggest that the use of self-deception following threat is constrained by the availability of contextual ambiguity (e.g., excuses). The effect of the excuse was not related to participants' mood or attributions for performance.