Alveolar ridge defects resulting from tooth extraction, trauma, or periodontal disease often require surgical correction prior to prosthodontic reconstruction. Whether implants or conventional fixed prostheses are planned, without careful consideration and proper treatment planning, hard and/or soft tissue defects may lead to functional, structural, or esthetic compromises in the final prosthesis. This article reviews the etiology and treatment of alveolar ridge defects and introduces a therapeutically oriented classification system of such defects (horizontal, vertical, and combination-HVC-classification). In addition, a decision-making guide for approaching each defect type will be discussed, and clinical examples of treated cases will be presented.