This study was conducted with a total of 158 students from 6th, 7th and 8th grades in two different secondary schools located in Siirt in the academic year of 2020-2021 to examine students' anxiety about the science lesson in terms of various variables and to determine the reasons for science anxiety. The study was conducted on the basis of a mixed design. While quantitative data were collected using the "Science Anxiety Scale (SAS)" and qualitative data were collected using the "Anxiety Form". Through the SAS, the anxiety levels of the students were determined and the relationship between the scale anxiety score and gender, grade levels, income levels and type of school was examined. The data collected by the SAS were analysed using the SPSS 26 package program. The content analysis of the data collected with the anxiety form was carried out. It was determined in the quantitative part of the research that there is no significant relationship between science anxiety and gender, 6th-grade students have higher science anxiety in the environmental sub-dimension compared to 7th and 8th-grades, and there is a significant relationship between family income level and type of school and anxiety scores, science anxiety decreased as the income level increased, and students studying at private school had less science anxiety. Based on the qualitative data of the study, anxieties of the study are mainly related to the science lesson, notably related to the exam, rote learning, hardness of lessons, the anxiety of falling behind in the class, and the homework. However, while some students have anxiety about the attitude and questions of teachers, others are instinctively anxious about giving wrong or no answers arising from attitudes and morale. While 3% of the students are anxious about everything, 14.9% are anxious about nothing. Their responses to the items of the questionnaire and the anxiety form are close in proportion, so it has been concluded that the quantitative and qualitative data of the study support each other.