The aim of this study was to examine the number sense performance of 8th-grade Turkish students. In this study, the students' performances on number sense were also examined in terms of gender, school location, parents' education level, maths achievement, perceived student satisfaction with the maths teacher, perceived importance of maths and perceived parental support for maths. Participants of this study consisted of 306 eighth-grade students (13- to 14-year-olds) from the western part of Anatolia in Turkey. The data were collected via the 'Number Sense Test (NST)' consisting of 38 multiple-choice questions and six number sense components. Data were analysed by using the Statistical Package for Social Sciences (SPSS) 17.0. The results from this study revealed that most of the students performed poorly on the number sense test and its components. No significant difference was found between female and male performances in number sense, but their performances significantly differed according to school location and parents' education level. The results of this study also indicated that a significant positive correlation was between the number sense performances of students and their maths achievement, perceived student satisfaction with maths teachers, perceived importance of maths and perceived parental support for maths.