Person-environment (P-E) fit theory is a general framework that has been used extensively to understand thinking and behavior in organizations. However, recent research has highlighted several important issues that compromise our understanding of the P-E fit construct. First, it is widely-assumed that affect is only an outcome of P-E fit. Second, our understanding of the antecedents to P-E fit is severely limited. Third, the non-correspondence between objective and subjective fit components has typically not been accounted for. In a bid to address these issues, this paper presents an expanded model of P-E fit which argues for and explicates a more important role for work-based affect (i.e. moods, emotions, and affective attitudes that are experienced at work) in P-E fit theory. Two perspectives are presented to account for why work-based affect can be a cause of P-E fit. The second part of this project reports on an empirical study that was conducted to investigate the causal effect of work-based affect on P-E fit together with other key relationships proposed by the expanded theory of P-E fit.