This paper attempts to provide an up-to-date depiction and analysis of the consumer’s attitude towards sustainability of fast fashion products in the UK. Four related strands of literature are reviewed to establish a tri-component model of attitude (ABC), i.e., Affective, Behavioural and Cognitive. A wide set of determinants for attitude is identified, including income, price, gender, culture, religion, age, etc. Based on this conceptual framework, an online questionnaire is designed and sent to university students and alumni in the UK, returning 128 valid responses. Both descriptive statistics and regression analysis (oprobit) are employed to shed light on the three components of attitude towards sustainability. It is found that cognitive and behavioural components converge across cultures and religions, but the affective component remains significantly diverse. Employment status contributes to the awareness, decision and feeling of sustainability features, but gender only matters for purchase decisions. In general, there is an improved cognitive and affective awareness of sustainability, but this does not automatically translate to purchase behaviour. Policy interventions like taxes and subsidies are still needed to foster sustainability in the fast fashion industry.