During the past decade, stereotypic behavior in horses, specifically crib-biting behavior, has received considerable attention in the scientific literature. Epidemiological and experimental studies designed to investigate crib-biting behavior have provided valuable insight into the prevalence, underlying mechanisms, and owner perceptions of the behavior. The findings of these studies have demonstrated how the management of horses can influence their behavior and well being. Management conditions which impede foraging opportunities and social contact, provision of high concentrate diets, and abrupt weaning have been associated with an increased risk of crib-biting. The exact etiology of crib-biting remains to be elucidated, however, results of recent research suggest that dopaminergic pathways may be implicated in the performance of this oral stereotypy. There has also been additional evidence to support the hypothesis that gastrointestinal irritation is involved in crib-biting in horses. Many equine behavior and welfare scientists remain in agreement that management of crib-biting horses should focus on addressing the suspected influential factors prior to attempts at physical prevention of the behavior. The findings of several survey and experimental studies are reviewed, with emphasis on research conducted since the late 1990s, in an effort to provide the reader with a relatively comprehensive look into that which is known about crib-biting behavior in horses. Knowledge deficiencies and areas for future research are identified.