Although taxi drivers are more exposed to traffic crashes, they usually exhibit riskier behaviors and more negative attitudes toward road safety. For example, previous research suggests that they are particularly reluctant to wear seat belts. The research aimed (a) to estimate the prevalence of seat belt use among taxi drivers compared to other professional and non-professional drivers (Study 1, n = 3.810) and (b) to explore attitudes toward seat belt use in taxi drivers using the Theory of Planned Behavior (TPB) (Study 2, n = 100). Study 1 showed lower seat belt use among taxi drivers (vs. other professional and non-professional drivers). Study 2 showed that self-reported use tends to be higher than the estimated observed use and that negative experiential attitudes appear to be essential for understanding the reluctance of taxi drivers to use seat belts. Practical implications and future lines of research are discussed.