The current research aimed at examining the mediating role of test anxiety in the relationship between teaching-learning conceptions and academic achievement. The correlation investigation model was adopted in this research. The participants of the research were volunteering teachers (n = 108) and students (n = 526) from five different high schools. For data collection, the "teaching-learning conceptions scale" (Chan & Elliott, 2004), the "Westside test anxiety scale" (Driscoll, 2007), and the "Grade point average determination form" were used. The data was analysed using hierarchical multiple regression analysis. According to the results obtained, it was found that there were significant relationships amongst teaching-learning conceptions, test anxiety, and academic achievement. Furthermore, it was concluded that test anxiety mediated the relationship between teaching-learning conceptions and academic achievement significantly.