Within the concept of sustainable development, ecotourism has emerged as a special form of tourism aimed at preserving and protecting natural and cultural resources, but also at contributing to the well?being of the local community. Although today the importance of ecotourism is recognized worldwide, there are countries that, despite their natural wealth and potential, have failed to popularize ecotourism. Considering that Serbia is one of them, the main goal of this research was to reveal ecotourism constraints and reasons which prevent domestic tourists from visiting eco?destination. In addition, the study aimed to determine how well the respondents are informed and familiar with the concept of ecotourism. To achieve that, the survey was conducted among 379 participants, residents of Serbia in September 2019. The constraining scale has been created, and by applying exploratory factor analysis, four factors have been singled out (Fears, Lack of resources, Lack of information, and Disadvantages of the tourism product). The findings showed that the biggest constraint preventing domestic tourists from visiting eco?destinations is inadequate waste disposal at such sites. It has also been found that the respondents are highly constrained by the lack of information, time, and money. The results also reveal the degree to which other factors contribute to non?visits to eco destinations, but also which of them do not have a key impact on tourists' decision to avoid such locations. The paper additionally discusses the potential impact of a lack of ecotourism knowledge on the respondents' answers regarding ecotourism constraints in Serbia.