The significant changes which have occurred in the competitive scenario in which fashion companies operate, combined with deep transformation in the lifestyles of final consumers, translate into the need to redefine the business models. Starting from a general overview of the emerging trends today affecting the fashion industry, the paper will devote particular attention to the analysis of the most important phenomena that are influencing this market and the drivers for long-lasting competitiveness: sustainability and attention to the so-called circular economy. According to the literature, from the consumer behavior's point of view, the younger generations are paying growing attention to these issues. In light of these considerations, this paper aimed to analyze how sustainability and circular economy principles are influencing the perception of the fashion world among the new generations of consumers. After mapping the emerging trends in the fashion industry and analyzing the role of sustainability from both the demand and supply side, this paper presents the results of a survey conducted through an anonymous questionnaire made in collaboration with Insubria University. The results of the survey describe the students' behaviour as regards fashion's emerging trends, with particular attention to sustainability issues and the application of circular economy principles. The survey results were analyzed from both a descriptive and quantitative point of view with the aim to check the different perceptions as regards sustainable fashion and circular economy in fashion, focusing mainly on the so-called Generation Z. The results of the analysis proved to be consistent with the theoretical framework and confirm the relevance of sustainability issues in the fashion industry today in driving the demand of Generation Z, by considering a gender perspective. Moreover, the circular economy is descriptively analyzed with the aim to understand the relevance of the different facets for the entire sample of respondents.