This study aimed to compare individuals diagnosed with major depressive disorder (MDD) with a healthy control group in terms of perceived financial threat and willingness to change financial behavior. It also examined whether the severity of depression in people with MDD affects perceived financial threat and willingness to change financial behavior, and how financial threat affects the willingness to change financial behavior. The study included 266 patients diagnosed with MDD and 266 healthy volunteers. The financial threat scale, the willingness to change financial behavior scale, and the Beck Depression Inventory are used. Results showed that individuals with MDD experience a higher perception of financial threat and a lower willingness to change financial behavior compared to healthy individuals. The severity of depression in individuals with MDD positively affects the perception of financial threat. However, this severity does not directly affect willingness to change financial behavior; instead, it creates an indirect effect through perceived financial threat. Moreover, perceived financial threat in MDD patients positively influences their willingness to change financial behavior. This study can make significant contributions to both behavioral finance and psychiatry literature in terms of revealing the effects of mental health on perceptions and behaviors regarding financial issues. The research offers new perspectives to develop practical implications on how mental health problems can be evaluated together with financial decision-making processes, how multifaceted evaluations can be conducted regarding the financial behavior of people with depression, and how predictions can be made by looking at both individuals and financial markets from these aspects.