This paper is the first of its kind to measure the income level of a country’s tourist arrival and empirically examine its impact on economic growth and environmental pollution in a sample of eight Mediterranean countries. The paper undertakes annual data from 1995 to 2014 and employs quantile regression models, autoregressive distributed lag (ARDL) estimations, and a heterogeneity causality test. The empirical results show that the income level of a country’s tourist arrival, across all quantiles, plays an important role in promoting economic development. However, the role of the income level of a country’s tourist arrival on environmental pollution varies with the changes in quantiles. More specifically, income level of a country’s tourist arrival has a positive impact on environmental pollution for the lower quantiles, while it has a negative impact for higher quantiles. The findings from panel ARDL models confirm that the income level of a country’s tourist arrival has positive and negative impacts on economic growth and emissions, respectively. Given these results, these findings provide information to take the necessary actions to ensure sustainable tourism development, i.e., the expansion of the tourism industry without harming the environment in the Mediterranean countries.