Ideas about why consumers tip some service occupations more often than others are tested using occupation scores derived from online ratings of 122 service occupations. Results indicate that U.S. consumers are more likely to tip occupations for which (i) workers’ performances can be more easily evaluated by consumers than by managers, (ii) workers provide customized service, (iii) workers’ income, skill and needed judgment are low, and (iv) workers are less happy than customers during the service encounter. Occupations with greater frequency of customer patronage and/or greater likelihood of encountering the same service provider on multiple service occasions are not more likely than other occupations to be tipped. These findings support some and disconfirm other expectations derived from a theory that occupational differences in tipping are attributable to occupation characteristics that more strongly/consistently evoke motives for tipping. They also identify types of services for which counter-normative tipping policies are more or less likely to be successful and suggest sources of resistance that must be overcome if those policies are to succeed.