Adult spinal deformity (ASD) is a complex pathology associated with spinal malalignment in the coronal, sagittal, and axial planes. Proximal junction kyphosis (PJK) is a complication of ASD surgery, affecting 10%-48% of patients, and can result in pain and neurological deficit. It is defined radiographically as a greater than 10° Cobb angle between the upper instrumented vertebrae and the 2 vertebrae proximal to the superior endplate. Risk factors are classified according to the patient, surgery, and overall alignment, but it is important to consider the interplay between various factors. This article reviews the risk factors of PJK and considers alignment-focused prevention strategies.