Current literature on the relationship between locus of control (LOC) and psychological well-being (PWB) consistently demonstrates that individuals with an internal LOC generally report experiencing greater psychological well-being than externally-oriented individuals. However, there is minimal depth of understanding regarding the specific dynamics of this well-established relationship. The aims of the present quantitative study were (a) to replicate and provide support for the existing knowledge on the relationship between these two factors and (b) to use a structural equation model (SEM) to further explore the relationship between LOC and the six dimensions in Ryff’s model of eudaimonic PWB, which are combined to assess one’s psychological welfare. Using cross-sectional survey methodology, 267 adult participants were recruited through convenience and snowball sampling to anonymously complete a series of questionnaires online. A Pearson r bivariate correlation analysis examining the relationship between PWB and LOC revealed a significant negative correlation between the two constructs (r = -.280, p = .001). This finding replicates previous research, where individuals with an internal LOC reported experiencing significantly greater PWB, while individuals with an external LOC reported significantly less PWB. In order to further examine how the six factors of PWB (self-acceptance, positive relationships, autonomy, environmental mastery, purpose in life, and personal growth) relate to LOC, a SEM was performed. Although all six dimensions of PWB show significant negative correlations with LOC, environmental mastery, self-acceptance, and purpose in life were the most impactful on the relationship between these two constructs, as they were shown to have higher significance in the SEM. Considering the SEM suggests that environmental mastery, self-acceptance, and purpose in life are the most weighted factors of PWB’s correlation to LOC, possible interventions on these factors in a clinical or applied setting may see improvement in the relationship between PWB and LOC.