Ataxia–telangiectasia is a rare, autosomal recessive primary immunodeficiency caused by mutations in the ATM gene on chromosome 11, which encodes a serine–threonine kinase essential for the recognition and repair of DNA double-strand breaks. The disease is characterized by progressive neurological impairment, immunological dysfunction, and an increased susceptibility to recurrent infections and malignancies. Pulmonary involvement represents a major source of morbidity and frequently arises from chronic infections, aspiration, and impaired airway clearance, ultimately leading to the development of bronchiectasis. The case of a 15-year-old adolescent with a history of recurrent aspiration pneumonias, neuropsychomotor developmental delay, and severe malnutrition is reported, who was admitted for evaluation of chronic productive cough, fever, and dysphagia. Comprehensive clinical assessment and ancillary investigations revealed recurrent respiratory infections, gastroesophageal reflux, and typical features of ataxia–telangiectasia, including cerebellar ataxia, oculomotor apraxia, and conjunctival telangiectasias. Additionally, bronchiectasis was identified as a secondary consequence of the underlying neurological and immunological impairment. This case highlights the diagnostic challenges posed by ataxia–telangiectasia in pediatric patients presenting with chronic respiratory symptoms and emphasizes the importance of early recognition of the underlying systemic disorder. A multidisciplinary approach is essential for accurate diagnosis and optimized management, aiming to address both the primary disease and its pulmonary complications.