Academics' conceptions of teaching (ACTs) and academics' teaching approaches (ATAs) are essential factors in informing academics' teaching behaviors. However, empirical evidence from longitudinal research exploring the causal link between ACTs and ATAs is lacking. In the current study, we employed a cross-lagged panel model approach in three waves to assess four hypotheses (i.e. stability, causal, reversed, and reciprocal models) concerning the causal association between ACTs and ATAs. For the data collection from 115 academics (60.9% female), we used the "Conceptions of Teaching and Learning" and the "Revised Approaches to Teaching Inventory." Our findings indicated that ATAs were a causal predictor of ACTs, not vice-versa, regardless of participants' gender and teaching responsibilities. Specific ATAs (i.e. student-centered or teacher-centered) predicted complementary ACTs in time. Our results reveal that conceptual changes in academics can be possible after observing the positive effects of a specific teaching method on student learning. Therefore, academic developers should help academics (especially novice teachers) accurately distinguish student-centered from teacher-centered teaching behaviors and learn how to apply specific student-centered teaching methods in conjunction with self-reflective techniques. More empirical longitudinal studies with sound designs are needed to understand better the multi-directional nature and influence between ACTs and ATAs over time.