This study was conducted to investigate the relationships among Turkish preservice science teachers' argumentativeness, epistemological beliefs, and achievement goals, as well as the reasons for coherencies and incoherencies among these variables. A sequential explanatory research design was applied within the 2 following studies. In Study I, the data from 930 preservice science teachers were investigated with structural equation modeling analysis. This analysis presented evidence regarding the relationships among the variables of the study. For example, preservice science teachers' scientific epistemological beliefs significantly predicted their argumentativeness and goal orientations. In Study II, 2 students were selected for each argument approach and argument avoidance cases. Data were collected through semistructured interviews and analyzed via a content analysis. The results of this study showed that participants' self-construal impacted the relationships among their argumentativeness, goal orientations and scientific epistemological beliefs. An investigation of a more comprehensive belief system model including preservice science teachers' self-construal is suggested considering the overall results.