This study focuses on the effectiveness of two types of teaching practices (i.e., inquiry-based and teacher-directed) on students' science achievement, an ongoing contentious issue in science education. It examined the direct and indirect effects of the two types of teaching practices, enjoyment of science, and students' science achievement with the US data of the 2015 Programme for International Student Assessment (PISA). Results indicated that both inquiry-based and teacher-directed teaching practices were significant and positive predictors of enjoyment of science. These three variables also significantly predicted science achievement. However, inquiry-based teaching practices were a negative predictor, whereas teacher-directed teaching practices and enjoyment of science were positive predictors of science achievement. The effects of the two types of teaching practices on science achievement were partially mediated through enjoyment of science but the path of inquiry-based teaching practices to achievement via enjoyment of science suggested a suppression effect. These results were further discussed in the US educational context.