Previous studies have suggested a possible connection between childhood trauma, the course of illness, and neurocognitive impairment in individuals with bipolar disorder (BD). This cross-sectional study aimed to investigate the relationship between childhood trauma and neurocognitive functioning in a sample consisting of 41 euthymic individuals with BD, 37 individuals who have at least one sibling with BD, and 48 healthy controls (HCs). We assessed childhood trauma history using the Childhood Trauma Questionnaire (CTQ). Both the BD and Sibling groups showed higher rates of emotional abuse, neglect, and higher total trauma scores compared to the HCs. A principal component analysis of the neurocognitive test battery revealed a global cognition factor responsible for 49.40% of the variance and five subsequent neurocognitive components: working memory & response inhibition, verbal memory, visual copying, verbal fluency, and processing speed. Individuals with BD had lower scores in verbal memory, visual copying, processing speed, and global cognitive factor domains than the Siblings and HCs. The Siblings' performance was similar to that of the HC group. Correlation analyses showed significant correlations between physical neglect, sexual abuse, and neurocognitive domains like processing speed, verbal fluency, working memory, and the global cognitive factor. However, the linear regression analyses didn't reveal a significant influence of childhood trauma on neurocognitive domains. Our findings indicate that both individuals with BD and their unaffected siblings have a high occurrence of childhood trauma, but presence of bipolar disorder itself appears to influence neurocognitive functioning independently of childhood traumatic experiences or familial predisposition to bipolar disorder.