Objective: Aim of this study was to determine the gender differences according to psychological and behavioral variables among 10th grade students in Istanbul/Turkey. Methods: Cross-sectional online self-report survey conducted in 45 schools from the 15 districts in Istanbul. The questionnaire included sections about demographic data and school life. Also depression, anxiety, anger, sensation seeking, assertivity and impulsivity subscales of Psychological Screening Test for Adolescents (PSTA) were used. The analyses were conducted based on the 4957 subjects. Results: Rate of males was 52.7% (n=2614). Mean age, sensation seeking and impulsivity scores were higher in males, whereas depression, anxiety, anger and lack of assertivity scores were higher in females. Rates of poor school success, disciplinary punishment, absenteeism, truancy before age of 13, physical harm from a friend, physical fight in last year, to bear arms and problem with the law were higher in males, whereas having suicidal ideation or attempt were higher in females. In logistic regression model, school related problems (poor school success, absenteeism and truancy before age of 13), delinquent behavior (physical fight in last year, to bear arms and physical harm from a friend), sensation seeking, and lower depression, anxiety, anger, impulsivity, lack of assertivity, and suicidal ideation differentiated males from females. Discussion: The findings suggest that females have higher psychological problems such as anger, depression and anxiety, which may also be related with suicidal thoughts, whereas males have higher school related and behavioral problems. [Anadolu Psikiyatri Derg 2015; 16(2.000): 77-84]