Kelly Services, Inc. is an American temporary staffing agency that operates throughout the world. It is headquartered in Troy, Michigan, and offers services that include temporary staffing services, outsourcing, vendor on-site and full-time placement. Kelly operates in 41 countries and territories. Kelly employs more than 530,000 individuals annually, in areas including office services, accounting, engineering, information technology, law, science, marketing, creative services, light industrial, education, and health care. Revenue in 2011 was $5.3 billion.