Pneumocephalus, air in the cranial cavity, is a common occurrence following cranial surgery. However, tension pneumocephalus, accumulation of air trapped in the cranial cavity causing a mass effect and abnormal neurological signs, is uncommon. Knowledge about conditions that contribute to tension pneumocephalus, a potentially fatal complication, including the related signs and symptoms, is imperative. Immediate collaboration with a physician allows for timely treatment and patient recovery. Treatment measures include preoperative teaching, immediate removal of intracranial air, supine positioning, administration of 100% oxygen, repair of the bony and dural defect, and, if indicated drain placement into the air cavity, temporary tracheotomy, and antibiotics.