This study focuses on pre-service science teachers' interpretations of graphs. First, the paper presents data about the freshman and senior pre-service teachers' interpretations of graphs. Then it discusses the effects of pre-service science teacher training program on student teachers' interpretations of graphs. The participants in the study were 117 preservice science teachers. Fifty-six of the participants were freshman. The data of the study were gathered with a questionnaire adapted from Aoyama (2007). The questionnaire includes two graphs each based on a different context, and having four questions about the interpretation of the graphs. The participants' interpretations of graphs were analysed in five levels. The levels were listed from low to high level: Idiosyncratic, Basic Graph Reading, Rational/Literal, Critical, and Hypothesising and Modelling. The results of this study reveal that preservice science teacher can read values and trends in graphs, but they are not successful at the higher levels within the interpretations of graphs hierarchy. Moreover, the Turkish pre-service science teacher training program does not promote student teachers' interpretations of graphs. These findings suggest that teaching modules should be designed to promote pre-service science teachers' interpretations of graphs and challenge them to go beyond basic graph reading. Furthermore, the factors that affect the pre-service science teachers' interpretations of graphs, such as the type of graphs and the context of the graphs, can be useful as the findings of the study can be used to aid in designing graphs teaching modules.