Pre-service biology teachers' intentions to teach evolution and factors influential in their intentions are analysed in this research in terms of the Theory of Planned Behavior (Ajzen, 2005), a socio-psychological theory. The research was conducted with 19 Turkish and 18 German pre-service biology teachers. For our purposes, semi-structured interview forms were used in interviews, and the results were analysed through the method of qualitative content analysis. It was consequently found that Turkish pre-service biology teachers' intention was under the ifluence of their attitudes and of their perceived behavioral control, that their low levels of perceived behavioral control would make the teaching of evolution difficult, but that they would try to carry on teaching despite the difficulty. It was further found that German pre-service teachers' intention of teaching evolution was shaped by their attitudes as well as subjective norms, that they mostly had the intention to teach the topic of evolution due to having subjective norms.