Shortages of satisfied and well-trained health care professionals are an urgent threat for health systems worldwide. Although numerous studies have focused on retention issues for nurses and physicians, the situation for the allied health workforce remains understudied. We conducted a rapid review of the literature on allied health workers to investigate the main reasons for leaving their profession. 1,305 original research articles were retrieved from databases MEDLINE, CINAHL, PsycInfo, and Epistemonikos, of which 29 were eligible for data extraction. Reviewed studies featured mainly pharmacists, psychologists, dietitians, physical therapists, emergency medical professionals, and occupational therapists. We categorized 17 typical factors of the intent to leave as organizational, psychological, team and management, and job characteristics. The relative importance of each factor was assessed by measuring its prevalence in the selected literature. By revealing common themes across allied health professions, our work suggests actionable insights to improve retention in these vital services.