Pocket can be defined as deepening of the gingival sulcus. If this happens due to coronal migration of the marginal gingiva it is called gingival or pseudopocket. Deepening due to apical migration of the junctional epithelium is referred to as true pocket. A sulcus depth up to 3 mm is considered to be normal, provided the patient can maintain oral hygiene. If it is increased beyond 3 mm it is called pocket. Periodontitis is always preceded by gingivitis, but not all gingivitis progresses to periodontitis. This chapter covers the classification of periodontal pocket, clinical features, pathogenesis, and histopathology of periodontal pocket. Pockets can be treated by new attachment technique, removal of the pocket wall, and removal of the tooth side of the pocket.