Depression is a prevalent and debilitating psychological condition that is one of the leading causes of disability worldwide. Severe life stress has consistently been found to precede the onset of depression, but not everyone who experiences severe life stress breaks down. Therefore, there must be moderators of life stress' depressogenic capability. There is suggestive evidence that the personality trait of introversion may moderate the depressogenic potential of interpersonal life stress, yet this personality domain is understudied. In the present research it was predicted that introverts experiencing a romantic break-up would be more depressed, have higher negative affect, and have lower positive affect than introverts without a break-up and extraverts regardless of break up. Two studies addressing these hypotheses found support for a moderating effect of introversion on the depressogenic potential of interpersonal life stress, but in the opposite direction. Possible explanations for these unexpected results and their implications are discussed.