The goal of this research is to investigate foreign language anxiety of the students learning English as a foreign language in preparation classes at Marmara University School of Foreign Language. In accordance with this aim, the students’ foreign language anxiety level and its differentiation according to their gender, academic achievement and participation in classroom activities were questioned. The research was designed in accordance with the correlational survey methods. The population of the research consists of 230 students who are in different levels and study in English preparation classes at Marmara University School of Foreign Language during the 2016-2017 academic year. The students who are absent in the classes on the research day and fill the scales incompetently or don’t fill them at all were eliminated and 215 students were reached. The students reached consists of 93,47 % of the population. Foreign Language Classroom Anxiety Scale was used to measure the students’ foreign language anxiety. Pearson correlation, t-test, ANOVA was used to analyze the data. The main results are: 1) The students’ foreign language anxiety is at the moderate level. 2) Female students’ foreign language anxiety is significantly higher than male students. 3) Students knowing two foreign languages have significantly lower foreign language anxiety than the students knowing only one foreign language. 4) Students’ foreign language anxiety changes according to their participation rate in reading and speaking activities in the classroom. Accordingly, it has been found out that the foreign language anxiety level of the students participating less in reading and speaking activities in the classroom is higher. And also, it is stated that the students’ foreign language anxiety does not change according to their participation rate in listening and writing activities in the classroom. 5) It has been stated that there is statistically meaningful and negative relationship between the students’ foreign language anxiety and their academic achievements they perceived and their final exam results. According to these results, it has been found that the students whose academic achievement they perceived are high had low foreign language anxiety. When the students’ final exam success is considered, it has been stated that the foreign language anxiety of the highly successful students is remarkably low compared to less successful and unsuccessful students.