<p>Comprehensive studies evaluating the effects of Brachial Plexus Birth Injury on functional level and activity participation from the perspectives of children and families are limited. This study aimed to examine the impact of injury type and functional level on activity participation and quality of life in children with Brachial Plexus Birth Injury, considering the perspectives of both children and their families. A total of 148 participants, including children aged 7–17&#xa0;years and their parents, were included in the study. The Narakas Classification was used to determine the type of injury. The Brachial Plexus Outcome Measure assessed activity and participation, the Mallet Scale evaluated function, and the Abilhand-Kids Questionnaire assessed hand skills. The Pediatric Disability Assessment Inventory Questionnaire evaluated activity participation and daily living skills, while the Pediatric Quality of Life Inventory Questionnaire was used to measure quality of life. According to the perspectives of parents/mothers, strong positive correlations were observed between Upper Extremity Function, Transfer/Mobility, Sports, Global Function, PEDI, and Abilhand-Kids parameters and children’s outcomes (r = 0.698, r = 0.639, r = 0.692, r = 0.736, r = 0.837, r = 0.76, respectively). Moderate positive correlations were also found between Pain/Comfort and Happiness/Satisfaction parameters (r = 0.46, r = 0.519, respectively). Investigating the relationships between parent and child parameters can enhance the effectiveness of treatment approaches and evaluation tools. A detailed analysis of these correlations may contribute to the development of new research areas and the improvement of existing treatment methods.</p>