This paper investigates one of the positive contributions of tourism to the economy through the lens of its influences on the shadow economy. Specifically, our study analyzes the effects of five indicators of tourism consumption (including domestic tourism spending, international travel and tourism consumption, business tourism spending, leisure tourism spending, and outbound tourism spending on the percentage of shadow economy to GDP) in 129 economies between 1996 and 2015. We find interesting results that contribute to the existing literature about tourism economics. Firstly, the development of the inbound tourism industry reduces the shadow economy significantly, while outbound tourism causes higher underground economic activities. Secondly, the influence of tourism on the shadow economy is significant in both the short-run and long run with a stronger effect in the long run. Thirdly, the effect of tourism on the shadow economy is more significant in the 42 High-Income Economies and 54 Low and Lower-middle Income Economies, while it is less obvious in the 33 Upper-Middle Income Economies. These findings have been checked by a battery of robustness checks ensuring their statistical consistency.