Background: Previous research suggests a relationship between teacher behaviors and students' effort. However, it is not clear what role the students' expectations (i.e., importance of teacher behaviors) play in this relationship. Objective: Utilizing the teacher behavior checklist, this study sought to investigate whether teacher behaviors mediate the relationship between the importance students set on teacher behaviors and students' effort. Further, the study explored which specific behaviors influence students' effort. Method: Cross-sectional survey data were analyzed (N = 159) using mediation analysis and stepwise multiple linear regression. Results: There was evidence that teacher behaviors mediate the relationship between the importance students set on teacher behaviors and students' effort. Four of the 28 teacher behaviors had a significant relationship to students' effort: creative and interesting, enthusiastic about teaching, happy/positive/humorous, and promotes critical thinking. Conclusion: Knowing students' expectations (i.e., the importance of teacher behaviors) is essential to increasing students' effort. Teaching Implications: Happy/positive/humorous had a negative relationship with students' effort, while creative and interesting, enthusiastic about teaching, and promotes critical thinking showed a positive relationship with students' effort.