A subset of marijuana smokers develop a cannabis use disorder and seek treatment for their marijuana use on their own initiative. A less well-known consequence of daily, repeated marijuana use is a withdrawal syndrome, characterized by a time-dependent constellation of symptoms: irritability, anxiety, marijuana craving, decreased quality and quantity of sleep, and decreased food intake. Treatment studies show that rates of continuous abstinence are low (comparable to relapse rates for other abused drugs), and more treatment options are needed. The objective of this review is to update clinicians on the current state of marijuana research and to describe features of marijuana withdrawal to facilitate the diagnosis and treatment of cannabis use disorders.