The purpose of this study is to determine the reasons of anxiety levels of high school students who learn French as a second foreign language. The sample of the study consisted of four hundred fifty-six students from two high schools in Denizli province in 2015-2016 academic year. In this study, the effects of variables such as learners' gender, class level, parents' educational background and occupation on the level of foreign language anxiety are examined. The results revealed that learners' anxiety levels are not affected by above-mentioned factors. However, it was found that medium- and low-level of anxiety have a positive impact on the student's learning processes. It was observed that anxiety levels of secondary school students influenced their academic performance. In conclusion, it was found in line with the literature that, depending on the level, anxiety has both positive and negative effects upon foreign language learning/teaching processes.