The participating students were enrolled in grades 9 and 10 in seven public high schools in various regions of the Australian Capital Territory. Personality was measured with a revision of the Junior version of Eysenck's Neuroticism, Extraversion, and Psychoticism scales. Delinquency was measured with the aid of Mak's (1993) 34-item Australian self-reported delinquency scale, which assesses the extent to which respondents have engaged in a range of marginally deviant to seriously delinquent activities over the past year. Two items were constructed to measure the participant's self-rated performance at school. Group identities were determined by asking respondents to indicate the extent to which they identified with two student groups. One was named the "studious/squares" group and described as "diligent students who are more interested in their studies than anything else, are keen to complete school work on time, know their stuff in class, are well prepared for examinations, and are popular with teachers." The second group was referred to as the "reckless/rebel" group, which was described as those who "question school rules and the limits set by their parents, are daring at school and on the streets, readily take risks and act impulsively, and at times get into trouble with their parents and teachers." In order to assess the ability of the various independent factors to predict self-reported delinquency, a hierarchical regression analysis was conducted. The findings confirmed the importance of psychoticism and a particular type of group identity in predicting self-reported delinquent behavior. A high score on "psychoticism" is associated with the severity and persistence of criminality, the external attribution of blame for criminal offenses, and a hindrance to psychological therapies. The dominant personality characteristic of individuals with a high score on psychoticism is aggressive-impulsive-unsocialized attitudes and behaviors. The students with a high frequency of self-reported delinquency also tended to identify more with the "reckless/rebel" group. In addition, "extraversion" (males) and low self-reported academic achievement (females) were important factors associated with self-reported delinquency. 3 tables and 28 references