<p>Self-referential processing bias (SRPB), self-assigned characteristics about oneself, may concurrently contribute to depression and psychological well-being. In the current study, we examined two hypotheses using structural equation modeling: self-critical rumination predicting depression and state self-esteem predicting psychological well-being because of SRPB. Participants (<i>n</i> = 133) were undergraduates between the ages of 18 to 32 (<i>M</i> = 19.97; female: 63.91%; White: 65.41%) who completed a three-part longitudinal study comprised of a baseline assessment of state self-esteem and self-critical rumination at T1, the Referential Encoding Task, a behavioral task validated to assess SRPB, at T2, and a one-week follow-up of depression and psychological well-being at T3. Although our initial findings did not support our hypotheses, a respecified model suggested that (1) a combination of SRPB and state self-esteem fully explained self-critical rumination’s ability to positively predict depression, (2) state self-esteem fully explained self-critical rumination’s ability to predict psychological well-being negatively. The findings suggest that state self-esteem and SRPB may be important behavioral targets to reduce depression and promote psychological well-being simultaneously – opening the potential for more efficient interventions and nuanced mechanisms of behavior change.</p>