Despite increasing enrollment, several groups of underrepresented (UR) college students underperform academically relative to their peers. I first review six psychological constructs that have been hypothesized to affect UR students’ academic performance, but which remain theoretically independent of one another. I then introduce the State Authenticity as Fit to the Environment model (SAFE; Schmader & Sedikides, 2018) as a theoretically integrative model that focuses on what causes people to thrive or to struggle in certain environments. In the third section, I discuss the similarities between the psychological processes thought to underlie currently studied constructs affecting UR academic performance and those purported by the SAFE model to determine psychological fit with an environment. I then introduce the Student Fit in College Environments (S’FICE) model – that I developed based on the SAFE model – as a framework for predicting UR college students’ academic performance. To test the S’FICE model, I developed a standardized instrument (the S’FICE instrument) to assess the psychological fit concepts central to the S’FICE model and provided preliminary evidence for its validity in Study 1. Study 2 was an experimental test of the causal role of the three components of psychological fit in increasing engagement within an academically relevant domain with Latina/o/x participants. Study 3 was a second round of instrument development to further improve the validity of the S’FICE instrument. Study 4 was a correlational, longitudinal test of the S’FICE model that assessed the ability of the three subcomponents of fit in academic contexts (as measured by the S’FICE instrument) to predict the actual academic outcomes of UR college students (again, Latina/o/x students) as well as their wellbeing (the latter dependent variable was an exploratory extension of the S’FICE model). Study 1 and Study 3 found significant validity for the S’FICE instrument. Apart from a minority of items, most items showed that they captured the measurement of self-concept, goal, or social fit. These results provided support for the use of the S’FICE instrument in measuring psychological fit when testing the S’FICE model. Study 2 and Study 4 provided consistent correlational support for the S’FICE model, but also suggested changes to the original relationships of the model. Confirming the predictions of the S’FICE model, each type of psychological fit was found to predict students’ engagement and therefore their academic performance, although each type of fit showed a more complex relationship to fluency and/or engagement than predicted. When wellbeing was tested, although all three types of psychological fit were found to predict wellbeing, social fit (feeling a sense of belonging among your peers), in particular, was found to have a direct relationship with wellbeing, whereas the other two types of fit related to wellbeing through motivational fluency (the ease with which goals are pursued). Motivational fluency was, in turn, directly related to wellbeing, thus showing that engagement did not mediate the relationship between psychological fit and wellbeing. Therefore, the S’FICE model predicting wellbeing differed slightly from the S’FICE model predicting academic performance. Study 4 also provided evidence to suggest that sub-components of the S’FICE instrument were the strongest predictors of UR academic performance and wellbeing in comparison to previously used instruments. In conclusion, psychological fit was found to be a significant predictor of both UR academic performance and wellbeing. The development and testing of this new model of UR performance in academic domains was intended to contribute both theoretically and practically to our understanding of UR students’ academic performance in college and to bridging the academic gap between UR students and their peers