P. L. Hewitt and G. L. Flett’s (1991b) model of perfectionism dimensions (i.e., self-oriented, other-oriented, and socially prescribed perfectionism) was compared with A. T. Beck’s model (G. P. Brown & A.T. Beck, 2002) of dysfunctional attitudes (i.e., perfectionistic attitudes [PA] and dependent attitudes [DA]) in predicting depression in 70 psychiatric patients and 280 university students. Socially prescribed perfectionism uniquely predicted both PA and DA. Dysfunctional attitudes failed to consistently predict additional variance in depression beyond perfectionism dimensions (and vice versa). Evidence for Hewitt and Flett’s specific vulnerability hypothesis and Beck’s specific cognitive vulnerability hypothesis was equivocal. Beck’s conceptualization of perfectionism as a unitary cognitive style obscures important information by overlooking the distinction between the self-related and socially based features of perfectionism. Hewitt and Flett’s conceptualization of perfectionism as 3 distinct personality traits allows for precise conclusions by recognizing the differential contribution of the self-related and socially based features of perfectionism.