The paper develops and tests theory that explains under what conditions the extent of email use is appraised as a stressor. Integrating concepts from information acquisition and person-environment fit theories, we hypothesize that individuals appraise their extent of email use as stressful based on the mismatch between their current and desired extents of email use. We define the mismatch as email misfit and the match as email fit. We first develop a conceptual framework that associates email misfit with the individual’s experience of three key workplace stressors—work relationships stressor, job control stressor, and job conditions stressor. We then develop hypotheses framing the relationship between email fit and misfit, and these stressors. We test our hypotheses by applying quadratic polynomial regressions and surface-response analysis to survey data obtained from 118 working individuals. The paper makes three theoretical contributions. First, in reporting a theoretical and empirical construction of email fit and misfit and their relationship to workplace stressors, it shows that email misfit is appraised as stress-creating. That is, both too much email and too little, compared to what the individual desires, are associated with stressors. Secondly, it shows that IT use (in this case, email) is appraised as stressful both when it exceeds (i.e., associated with overload) and fails to meet (i.e., associated with underload), the user’s expectation and preference. Thirdly, this paper suggests the person-environment approach as a theoretically novel way to conceptualize the cognitive appraisal and judgement associated with information underacquisition and overacquisition and shows workplace stressors as potentially new effects associated with them.