OBJECTIVES:  To use the Theory of Planned Behavior (TPB) to predict university students’ intention to use emergency contraception (EC).  METHODS: A web-based survey was pretested and emailed to 2,000 university students in May 2010.  The web-based survey measured the essential components of the Theory of Planned Behavior: intention, attitude (A), subjective norm (SN), and perceived behavioral control (PBC).  The independent variables, A, SN, and PBC, were measured directly as well as by belief-based (indirect) measures.  In addition, a measure of recent past behavior was evaluated.  RESULTS: An overall usable response rate of 21.0% was obtained.  In general, university students intended to use EC should the need occur, held favorable attitudes toward the use of EC, were somewhat influenced by social norms regarding EC use, and perceived themselves to have some control over EC utilization.  For direct measures (TPB), A, SN, and PBC were significant predictors of intention to use EC.  The direct model explained 49.2 percent of the variance in intention.  Using indirect measures, A and SN were significant predictors of intention, but PBC was not; the indirect model accounted for 41.3% of the variance in intention to take EC.  Attitude was the strongest TPB predictor for both models, followed by SN and PBC.  The RPB variable did not significantly improve the TPB model.  CONCLUSIONS: In summary, this study identified several key factors that partially explain why university students either intend or do not intend to use EC if needed.  The TPB has utility in predicting utilization of EC in university students.  Focusing particular attention on A, as well as SN and PBC, will allow researchers, educators, healthcare professionals, and legislators to develop strategies and educational programs to enable men and women to use EC responsibly.