Besides algorithmic thinking is a basic mathematical skill that places on the centre of processes which has great importance today, such as problem solving, programming and coding, it is seen that studies related to algorithmic thinking in the literature are very limited. In this context, this study aims to investigate the algorithmic thinking skills of secondary school students according to different variables. This is a case study and the study group consist of 138 students in total studying at 5th and 6th grades of different public secondary schools in the province of Ordu. Roughly, fifty-four and forty-five percent of the study group consist of female and male students, fifty and forty-nine percent of them consist of fifth and sixth graders respectively. Criteria sampling method of objective sampling methods was used in determining the study group and Algorithmic Thinking Test developed by the author as data collection tool was administered to the students in the study group. As a result of the study, it was found that there is a positive but low level of correlation between the algorithmic thinking skills and mathematics achievements of students. There were also significant differences in favor of female students and 6th grade students between the algorithmic thinking skills of the students according to gender and grade level variables respectively. At the end of the study, some recommendations were presented according to obtained results and for relevant studies that can be carried out about the subject in the future.