From a mainstream economic perspective, tipping is often seen as a rather anomalous or irrational economic activity since consumers could legally and willingly avoid paying tips altogether. Nevertheless, this pervasive economic activity generates tens of billions of dollars in income a year, worldwide. In order to better understand this seemingly irrational behavior to tip, this study investigates other potential motives for tipping that draw from the behavioral economics and psychology literature. We test several of these motives in the context of tipping car guards in South Africa and find evidence supporting the ideas that tipping is motivated by desires to: reward good quality service, help service workers, and gain social approval.