The validity and clinical significance of the characteristics of borderline personality disorder (BPD) in adolescents are increasingly being recognized. The persistence of BPD characteristics in adolescence is high and is associated with negative interpersonal, academic, professional, and financial outcomes. In the literature, BPD characteristics observed in children and adolescents are explained with psychodynamic theories, developmental models, and evolutionary approaches. Emotional dysregulation, interpersonal dysfunction, impulsivity, and self-harming behavior, negative life events, temperament characteristics, neuropsychological dysfunctions, neuroanatomical, genetic, hormonal, and immunological factors may play a role in BPD etiopathogenesis. This review aims to address different approaches and relevant factors for the development of BPD. The articles published between 1968-2021 in the PubMed database were reviewed, and prominent studies were selected for evaluation. The importance of invalidating environment, epistemic freezing and hypermentalization, complex or attachment trauma is emphasized in psychodynamic and developmental literature. In the evolutionary approach, on the other hand, romantic relationships and the onset of reproduction are emphasized as the reason for the emergence of symptoms during adolescence, and it is argued that BPD is related to the rapid life history strategy. It is stated that a decrease in volume in the orbitofrontal cortex and anterior cingulate cortex, which are involved in top-down emotional processing, and an increase in the activity of thalamus and hippocampus regions, which are involved in bottom-up emotional processing are observed in adolescents with BPD characteristics when compared to healthy controls. It is thought that the increase in activation in the superior temporal gyrus and precuneus observed in adolescents with BPD features is a neural indicator of hypermentalization, and the increase in activation in the insula is a neural indicator of social pain. It has been reported that the decrease in resting heart rate and the increase in heart rate variability observed in adolescents with BPD symptoms are associated with the activation of the parasympathetic system. BPD in adolescents is a disorder that challenges clinicians in terms of diagnosis, differential diagnosis, and treatment. It is crucial to evaluate the factors related to etiopathogenesis in BPD in a multifaceted and detailed manner. Keywords: Borderline Personality Disorder, Difficulty in Emotion Regulation, Mentalization, Trauma, Self-harming Behavior, Temperamental Characteristics.