In this study, it was aimed to determine the critical writing skill levels of fourth grade Primary School students. This study is a quantitative research and was designed in a scanning pattern. The study group of the research consists of 175 students attending in the fourth grade of three different Primary Schools, which were determined by the purposive sampling method, by taking into account their gender and socioeconomic status. The research data were obtained as a result of the evaluation of the critical writings written by the students in the study group with using the critical writing rubric. The obtained data were presented as descriptive statistics (frequency, min. and max. values, arithmetic mean, standard deviation) with the help of statistical program, and analyzed with independent samples t-test and one-way analysis of variance (ANOVA). As a result of the research, it was determined that the students' scores on critical writing skills were generally at a low level. In general, students are insufficient in the dimensions of planning, presenting evidence and persuading, questioning, and multidimensional thinking of critical writing; fluency and clarity and shape/form dimensions were found to be sufficient. In addition, it was determined that student achievements differed significantly according to socioeconomic level (in favor of high socioeconomic level) and gender (in favor of female students).