Abstract Women are twice as likely as men to suffer from a major depressive episode. Reasons for this gender difference in propensity for depression are not completely understood, although a number of explanations have been articulated. In this article we focus on two constructs that have been linked to gender differences in depression - ruminative cognitive style and interpersonal dependency. Ruminative cognitive style refers to the tendency to respond to depressed or dysphoric mood with repetitive thoughts and behaviours that focus attention on the meaning and consequences of the depressed mood (Nolen-Hoeksema, 1991). Interpersonal dependency reflects an investment in relationships and communion. We propose a theory of how these constructs interact to increase women's propensity to develop depression. Gender difference in rates of major depression is a consistent research finding, with women being about twice as likely to suffer from a major depressive episode as men (Kessler, McGonagle, Swartz, Blazer, & Nelson, 1993; Nolen-Hoeksema, 1990, 1995; Weissman & Klerman, 1977). This difference in rates of depression in women relative to men emerges in mid-puberty and remains throughout adulthood (Daley & Hammen, 2002; Daley, Hammen, & Rao, 2000; Kessler et al., 1993; Nolen-Hoeksema & Girgus, 1994). women are more vulnerable to depression than men is not completely understood, although various biological, social, and psychological explanations have been offered. Hormonal changes during puberty, childbearing years, and menopause, for example, are suspected to have some connection to increased depression in women (Denmark & Paludi, 1993; Formanek & Gurian, 1987; Seeman, 1997). Societal gender inequity and the oppression of women (e.g., poverty, lower social status, vulnerability to sexual and physical abuse) have also been linked to adverse mental health outcomes for women (Murphy, 2003). There are many plausible reasons and explanations as to why women are more vulnerable to depression than men, and no one explanation can reasonably account for this difference. In this article we explore and focus specifically on two constructs that have been linked to gender differences in depression - ruminative cognitive style and interpersonal dependency. We first review research outlining the relation between depression and ruminative cognitive style and between depression and interpersonal dependency. Although these topics have been reviewed previously, we contribute to this literature as we also propose a theory of how these constructs interact to produce a woman's increased propensity to develop depression. Theories of gender differences in depression have historically focused on individual variables without considering interactions between variables, and investigators have stressed the importance of examining integrated models (Nolen-Hoeksema, 1991). Ruminative Response Style Nolen-Hoeksema proposed that gender differences in depression could be accounted for by differences in the ways in which women and men respond to depressed or dysphoric mood (Nolen-Hoeksema, 1987, 1991, 2001; Nolen-Hoeksema & Jackson, 2001). Response Style Theory (RST) posits that women are more prone to ruminate in response to depressed or dysphoric mood than are men, whereas men are more prone to distraction in response to depressed or dysphoric mood than women (Nolen-Hoeksema, Larson, & Grayson, 1999). Rumination can be defined as repetitive thoughts and behaviours that focus individuals' attention inwardly on the symptoms of their depressed mood as well as on the meaning and consequences of these symptoms. Examples of rumination include focusing on how depressed and unmotivated one feels (I feel so down that I have no energy or interest to do anything), wondering why one is feeling so down and depressed (What is wrong with me? Why do I feel so sad?), and worrying about the consequences of the symptoms of depression (Things will never work out for me). …