Lymphatic malformations (LMs) are one of the congenital malformations of the lymphatic system in the body. The patient usually presents with head and neck swelling, airway compression, and/or airway obstruction. The diagnosis of retropharyngeal LMs can be challenging due to their rare occurrence. We report a case of a five-month-old boy diagnosed with retropharyngeal LMs. He presented with a three-day history of fever, cough, and stridor and was initially treated for acute bronchiolitis. A lateral neck radiograph revealed prevertebral widening, suggesting retropharyngeal collection. The patient's condition worsened, requiring intubation in the operating room and proceeding with aspirations and drainage. However, the symptoms recurred after a few days, necessitating re-intubation, repeated aspirations and drainage procedures. The patient was intubated, and the neck's magnetic resonance imaging (MRI) confirmed retropharyngeal LMs. An elective tracheostomy was performed and was treated with sirolimus. The patient had a successful tracheostomy decannulation and showed no recurrence during follow-up.