Using an Internet daily diary methodology, this study tested the goodness of fit hypothesis, which highlights the importance of the match between controllability appraisals and coping efforts in adjustment to stressful events. For 28 days, 190 undergraduates described their most stressful event and its controllability, how they coped, and their daily positive and negative mood. Individuals demonstrated fit across situations, with control appraisals associated positively with problem-focused coping and negatively with emotional approach coping and avoidance coping. A pooled within-person interaction indicated that problem-focused coping had a stronger positive association with positive mood when dealing with high versus low control stressors. Significant variation also was found in several other within-person interactions between control appraisals and coping, and some evidence was found for the notion that individual differences in the degree of matching coping to control appraisals were associated with person-level adjustment.