Computational-thinking can be defined as a way of understanding the problem solving, system designing and human behaviour as well through the concepts of basic computer science. In today’s information age, computational-thinking skills are expected to exist among the commonly-used basic skills such as reading, writing, logics and mathematics. The main aim of the study, within this context, is to emphasize the significance of computational-thinking and examine the computational-thinking skills of High School students with regard to the variables of High School types, class levels and gender. The sample of the research, designed in accordance with descriptive survey model, consisted of 445 students in total from three different High Schools within 2016-2017 School-Year Fall Term. Computational-thinking skill scale was utilized to collect the data. Mann-Whitney U and Kruskal Wallis tests were conducted in statistical calculations. The results of the study indicate that High School students consider themselves sufficient at a medium-level regarding their computational-thinking skills. The results also suggest that the computational-thinking levels of the students display meaningful difference with respect to the type of the High School they attend. However, no meaningful relation is found to be existing between the computational-thinking skills of the students and the class-level or gender variables.