This paper identifies the determinants of OECD Environmental Policy Stringency (EPS) index using a panel of 21 European countries for the period 2009-2019. If there is a large literature on the macroeconomic, political, and social determinants of EPS, the people’s attitudes or preferences toward environmental policies is still burgeoning. Thus, the main goal of this paper is to estimate the effects of people’s awareness regarding environmental issues on the EPS indicator. Due to the endogeneity of preferences, we have applied an instrumental variable framework to estimate our empirical model. Our most important result is to show that individual environmental preferences have a positive and significant effect on the level of EPS indicator : on average, a rise in individual preferences of 10% in a country will increase its EPS indicator by 2.30%. Our results have important policy implications.