Background An increase in self-destructive and aggressive behaviours in adolescents has been observed in recent years. The present study focused on self-perception of adolescent girls who show different types of extreme destructive behaviours (suicidal or violent). The main aim of the study was to identify personality predictors of suicidal and violent behaviour in adolescent girls. Participants and procedure The study involved 163 female participants aged 13-17 years, including 44 suicide attempters (without extreme aggressive behaviour towards others), 46 girls using violence against others (without extreme self-destructive behaviour) and 77 girls exhibiting no destructive behaviour. The following research methods were applied: the Adjective Checklist (ACL) (versions “What am I like?” and “What would I like to be?”), and the Sentence Completion Test. Results The girls showing extreme destructive behaviour, particularly self-destructive behaviour, were found to have a more negative self-image, a lower level of consistency of the self-image, lower self-esteem and a higher level of inner conflict than the control group. Stepwise discriminant analysis was used to determine predictors of extreme self-destructive or aggressive behaviours. Escalated inner conflicts within the attitude towards oneself appear to be the most important predictor of suicidal behaviour in adolescent girls, whereas self-perception based on strength seems to be the most significant predictor of violent behaviour in adolescent girls. Conclusions The research showed that destructive behaviour among adolescents is a multidimensional phenomenon. The statistical model presented in the study has been proved to have a high value. The results can help in successful prevention and therapy of destructive behaviours in adolescents.