Social-cognitive career theory (R. W. Lent, S. D. Brown, & G. Hackett, 1994) postulates that changes in self-efficacy precede changes in interests, but the cross-sectional nature of most research has precluded the examination of temporal precedence in the relation between these variables. The authors assessed college students' career interests and self-efficacy at 3 separate times over the course of an academic year and examined the temporal nature of the relationship using a cross-lagged panel design. Structural equation modeling with observed variables generally revealed a reciprocal relationship between the 2 constructs over time, but the temporal precedence was inconsistent across time periods. The authors discuss these results in the context of A. Bandura's (1986) self-efficacy theory and provide recommendations for theory refinement and career counseling practice.