Substantial research has examined self-regulatory processes across individuals (e.g., Locke & Latham, 1990) and several recent studies have explored these processes within individuals across time (e.g., Donovan & Williams, 2003; Ilies & judge, 2005). The current study combined these perspectives, investigating individual differences in reactions to goal-performance discrepancies over time. Specifically, this research examined the moderating effects of individual differences in achievement-related beliefs (locus of control and general self-efficacy) and motivation (conscientiousness) on goal- and effort-related responses to goal-performance discrepancies. University students (N = 90) first completed online measures of these personality characteristics, and then responded to questionnaires assessing goals, effort, and performance for an undergraduate class over the course of a semester. Hierarchical linear modeling analyses indicated that the reactions to goal-performance discrepancies observed in prior studies were influenced by these personality characteristics, leading to different patterns of self-regulation over time. (C) 2009 Elsevier Ltd. All rights reserved.