Tipping in U.S. restaurants alone amounts to $27 billion annually. Tipping is also common in other occupations and countries, making tipping a significant economic activity. The literature on tipping is spread over various disciplines: mainly psychology, economics, hospitality, and tourism. This survey article integrates the research conducted on tipping to allow an overview of the literature. In addition to summarizing and synthesizing the research on tipping, the article includes original ideas and suggests topics for future research.