We examined whether support underprovision (receiving less support than is desired) and support overprovision (receiving more support than is desired) should be examined as qualitatively distinct forms of inadequate support in marriage. Underprovision of partner support, overprovision of partner support, and marital satisfaction were assessed 5 times over the first 5 years of marriage in a sample of newlywed husbands and wives (N = 103 couples), and were analyzed via actor-partner interdependence modeling (APIM) and growth curve analytic techniques. Increases in underprovision and overprovision of support were each uniquely associated with declines in marital satisfaction over the first 5 years of marriage; however, overprovision of support was a greater risk factor for marital decline than underprovision. Further, when examining support from a multidimensional perspective, overprovision was at least as detrimental, if not more detrimental, than underprovision for each of 4 support types (i.e., informational, emotional, esteem, and tangible support). The present study is the first to examine the utility of differentiating between underprovision and overprovision of partner support. Theoretical, empirical, and clinical implications are discussed.